Asthma is the most common chronic disease in children and the effects of air pollution exposure on asthma and respiratory health in children have been a growing concern over recent decades. Although a number of epidemiological studies have been carried out in this field, these have produced conflicting results. The aim of this study was to assess the effects of long term exposure to nitrogen dioxide (NO2) and particulate matter (PM10) on asthma prevalence and lung function in children. To achieve this, a novel exposure model was developed and evaluated, which allowed retrospective exposure assessment of children participating in a population based birth cohort study – the Manchester Asthma and Allergy Study (MAAS). MAAS is a prospective birth cohort study comprising 1185 children specifically designed to study asthma and allergies. Clinical follow up took place at ages 3, 5, 8 and 11 years. At each follow up parents completed questionnaires on asthma diagnosis and symptoms and children underwent skin prick tests for common allergens. Children’s specific airways resistance (sRaw, at ages 3, 5, 8, 11) and forced expiratory volume in one second (FEV1, at ages 5, 8, 11) were measured. At ages 5 and 11 years FEV1 was measured at baseline and after bronchodilator treatment. The exposure model developed during this study incorporated outdoor and indoor air pollution, spatio-temporal variation in air pollution and time-activity patterns of children. The model was based on the concept of microenvironmental exposure. It modelled personal exposure based on PM10 and NO2 concentrations in children’s home, school and journey microenvironments (MEs) and the length of time they spend in these MEs. Land use regression (LUR) models were used to model PM10 and NO2 concentrations in outdoor MEs. These LUR models were specifically developed for the Greater Manchester area. A novel method was used to develop the LUR models, which used the output from an air dispersion model as dependent variables in the regression analysis. Furthermore, a novel approach was used to obtain annual concentration of PM10 and NO2 from 1996 to 2010, which involved the recalibration of the LUR models for each year. A mass balance model and indoor to outdoor ratios were used to model concentrations in indoor MEs. The performance of the exposure model was evaluated through a personal monitoring study in schoolchildren attending a local secondary school. Children wore personal NO2 monitors for two consecutive days in four seasons. Parental questionnaires and time-activity diaries were used to obtain information for the exposure model and to model NO2 exposure for the same time period. The results showed good agreement between monitored and modelled NO2 concentrations (Normalised mean bias factor=-0.04). Multiple linear regression and generalised estimating equations (GEE) were used to assess the cross-sectional and longitudinal effect of modelled exposure on sRaw and FEV1 (as % predicted). Multiple logistic regression and GEE were used to assess the effect of modelled exposure on the prevalence of asthma and current wheeze.The longitudinal analyses showed significant associations between PM10 and NO2 exposure and % predicted FEV1 (PM10: B=-1.37, p=0.019; NO2: B=-0.83, p=0.003), but no association with sRaw (PM10: B=0.009, p=0.37; NO2: B=-0.007, p=0.16). The cross-sectional analyses showed no association between pollutant exposure during the summer or winter prior to age 11 and any of the lung function measures (p>0.05). Long term PM10 or NO2 exposure were not associated with asthma or current wheeze (p>0.05).This study developed and evaluated a novel air pollution exposure model for epidemiological research. The results of this study suggest a negative impact of long term exposure to NO2 and PM10 on growth in FEV1 during primary school age. However, no evidence of an association between long term exposure to NO2 and PM10 and childhood asthma was found.

This paper provides a risk assessment of pertinent toxic contaminants in the tailings of the Iron King Mine using a model of aeolian transport fated in human alveolar lung. Here, we studied particulate matter of tailings that are 10 microns (𝜇𝑚) or less in diameter (𝑃𝑀₁₀) because these is most hazardous fraction. We used in-vitro bioaccessibility and in-vivo Microtox® data to determine the relationships between chronic inhalation of these tailings. Our data suggest that arsenic and zinc are the two principle drivers for toxicity of the Iron King Mine’s PM₁₀ tailings and that arsenic will solubilize in human alveolar biofluids at the expense of other noteworthy elemental contaminants in the tailings. The principle contaminant of concern for chronic exposure is arsenic, due to its increased bioaccessibility over time. Our data show that synthetic lung fluid (SLF) mitigates the toxic effects of arsenic, despite its increase in bioaccessibility over time. Therefore, we suggest a buffering mechanism of phosphate competition with arsenate to explain this mitigation of toxicity in SLF. We conclude that public health risk of chronic inhalation of IKM PM₁₀ tailings may be less severe than would otherwise be suggested by high concentrations of toxic contamination in the tailings impoundment.

In general, people prefer information that makes them look and feel good. This is information that is consistent with, or supportive of, their desires, beliefs, and behaviors. Much research has been devoted to examining biases in how we selectively seek some information and avoid other information as well as different factors that can mitigate or intensify these tendencies. The present project explored the impact of feeling powerful—a psychological experience shown to influence cognitions and behavior—on decisions about what information people choose to consume in a health context. Specifically, this was investigated in two different domains of health information consumption—selective exposure (Studies 1 & 2) and information avoidance (Studies 3 & 4). The first two studies investigated if feeling powerful affects selection of, or interest in, information known to be consistent or inconsistent with beliefs and behaviors. It was predicted that power would increase interest in belief-consistent (i.e., non-threatening) information. The final two studies examined how power impacts decisions about whether to receive or avoid an uncertain piece of health information that is potentially threatening. Contrary to selective exposure hypotheses, it was predicted that power would increase interest in this uncertain (i.e., threatening) information. All four studies revealed null largely effects of power, suggesting that feeling powerful may not influence how people chose to consume potentially threatening health information. A discussion of the potential limitations of these studies and the scope of this conclusion are included.

The repair of automobiles is a critical aspect in vehicle ownership and is potential source of volatile toxic compounds being brought into a home when repairs are conducted in an attached garage. The goal of this study was to assess the impact of the repair of automobiles in an attached garage on the exposure of the home mechanic and degradation of indoor air. Five common automotive tasks were performed in two garages with the garage door either opened 30.5 centimeters (n=5) or closed (n=4). The exposure to the home mechanic, the behavior of contaminants within the garage, and infiltration of contaminants in the home were the determinants of interest. Integrative sampling incorporating charcoal sorbent sampling tubes analyzed by gas chromatography and directs reading photo ionization detectors were used to assess exposure. The tasks with the greatest contributions to the home mechanic’s exposure were found to be brake pad replacement and oil change; these generated 95th percentile concentrations of 51.2 ppm and 12.8 ppm, respectively, with the garage door closed. In contrast, the tasks of refueling and shock replacement had 95th percentile contributions of 0.85 ppm and 2.99 ppm, respectively, in the closed garage. Equations were fitted to the aggregated concentrations during decay to estimate general ventilation (Q/V) in a closed garage. The contaminants within the garage were not found to infiltrate into the home as the average concentrations within the home never exceeded 1 ppm. It was found that automotive repair work in a closed garage may constitute up to 18% of threshold limit value of toluene over a 105 minute exposure at home. Automotive repair inside an attached garage has the potential to make a significant contribution to a mechanic’s daily exposure and should be incorporated into occupational exposure assessments of volatile organic compounds.

The overall goals of this doctoral dissertation were to 1) assess effects of nanoparticle (NP) exposure on host defense in a murine pulmonary infection model, 2) evaluate an integrated dynamic in vitro exposure system (DIVES) that overcomes limitations of submerged exposure systems for NP toxicity testing and 3) provide information on the rank of NP toxicity and assess the potential of the DIVES as a screening tool for NP toxicity. To achieve the first goal, we used Klebsiella pneumoniae (K.p.) in a murine lung infection model to determine if pulmonary bacterial clearance is enhanced or impaired by copper (Cu) NP exposure. Cu NP exposure induced strong inflammatory responses and an impairment in host defense against bacterial lung infections in both inhalation and instillation exposure studies even though there was an upregulation of pro-inflammatory cytokines and recruitment of neutrophils to the lungs. Thus, Cu NP exposure may lead to increased risk of pulmonary infection by impairing host defense against bacteria. In the second study, we integrated the DIVES capable of generating NP aerosols and depositing NPs directly onto cells grown at the air-liquid interface (ALI) to mimic a more realistic in vivo pulmonary exposure to inhaled NPs. Furthermore, we characterized the efficiency of NP delivery, the distribution of particle deposition and the effects of exposure conditions in the DIVES on the viability of A549 cells (human alveolar type-II-like cancer cells) as a precursor to studies of NP toxicity. The DIVES was shown to provide efficient, uniform and controlled dosing of particles to epithelial cells grown at the ALI. In addition, this exposure system delivered a continuous airborne-exposure of NPs to lung cells without loss of cellular viability. Lastly, to assess the DIVES as a means to rank NP toxicity and prioritize NPs for in vivo testing, we compared in vitro measurements obtained using the DIVES and the submerged exposure system to in vivo results obtained using a murine model of lung inflammation. Exposure to Cu NPs induced a significant increase in cytotoxicity and inflammatory responses compared to Fe NPs at the ALI in the DIVES. The results of this comparison suggest that air-delivery of NPs to lung cells using the DIVES can provide evidence of toxicity at a lower concentration of NPs compared to responses in the submerged condition. More importantly, our in vitro results presented in this dissertation are in agreement with our in vivo findings showing that Cu NPs have a higher propensity for NP dissolution and this may contribute to the greater toxicity of Cu NPs than Fe NPs. Thus, the results of these comparisons suggest that the DIVES has a significant potential for screening NP toxicity and allows for a higher throughput than in vivo studies. Overall, we found that exposure of lung cells at the ALI using the DIVES is preferable to submerged exposure for in vitro NP toxicity testing and provides useful information on the rank of NP toxicity and prioritization of NPs for in vivo testing.

Exposure therapy is the gold standard treatment for anxiety disorders, but reductions in fear following exposure often do not generalize well outside the context in which they took place. This study tested a strategy for increasing generalization that involved revisiting the memory of a prior exposure experience in order to enhance the retrieval of the learning that occurred. Forty-five participants (29 females, 16 males) with claustrophobia received exposure training consisting of repeated 5-minute trials lying inside a narrow cabinet laid on its back. One week later, they were randomly assigned to either enhanced mental reinstatement (EMR) or control procedures. Results of the exposure training showed significant decreases in subjective fear, heart rate and avoidance in the training context, as well as reduced claustrophobia symptoms. As expected, fear levels in the mock MRI scanner one week later increased relative to the exposure training context post-treatment. Compared to the control condition, the EMR intervention led to significantly reduced heart rate reactivity in the mock MRI scanner, but not to reduced self-reported fear or avoidance of the mock scanner, nor to differences in claustrophobia symptoms at one-month follow-up. Expectancy violations about coping self-efficacy, measured via participants’ surprise about their ability to effectively cope during exposure, predicted lower fear in the mock MRI regardless of condition. Fear-related expectancy violations, reflecting greater discrepancy in expected vs. actual fear levels during exposure, predicted greater fear in the mock MRI. Results highlight the potential for mental reinstatement of exposure to improve generalization of learning in claustrophobia, though effects may be limited. The impact of expectancy violations on exposure outcomes may depend on the type of expectancy that is violated.

>Magister Scientiae - MSc / Engineered nanomaterials derived from various bulk materials are being developed in ever larger quantities and with very diverse chemical compositions. The physical and chemical properties of the smaller nanoparticles are very different compared to their larger bulk chemicals. Titanium dioxide nanoparticles (TiO2NPs) are an example of such an engineered nanomaterial. Titanium dioxide nanoparticles are mainly used as a pigment in many applications such as glazes, enamels, plastics, pharmaceuticals, cosmetics, and it is widely used in sunscreens. Human exposure to TiO2NPs can occur both during manufacturing and use.

Although the negative associations between marital conflict and children’s adjustment are well documented, less is known about how marital conflict styles (e.g., engagement, withdrawal, problem solving and compliance) are related to children’s developmental outcomes. The present study seeks to determine what types of parents’ conflict styles, during the child’s first year of life, are related to children’s behavioral outcomes in the first grade. Analyses examine the hypothesis that more conflictual conflict resolution styles of parents during a child’s infancy will predict poorer child outcomes over time. In addition, given the growing literature documenting the first year of life as a particularly sensitive period in children’s development, the proposed study will explore the effect of parents’ conflict resolution styles in the child’s first year of life on child outcomes at age six, controlling for concurrent levels of conflict. Lastly this study will explore the interaction of parents’ conflict resolution style in predicting children’s outcomes. Conflict resolution style and children outcomes were examined in a sample of 153 working-class, first-time parents and their children. Participants were recruited through prenatal classes at hospitals and birth clinics, as well as through Women, Infants, and Children (WIC) offices in Western Massachusetts.

Outside to the wide range of potential benefits, the use of nanomaterials can endanger human health and the environment. This diploma thesis presents the results of pilot measurements, where the exposure of nanoparticles was monitored. Based on a literature research a suitable method for measurement was the three-stage OECD model. Based on this model, measurements were performed in three welding workplaces, where nanoparticles are produced incidentally. The measurement consisted of collecting information and measuring the concentration of nanoparticles in the workplace, where data collection was focused only on inhalation exposure. During welding, 0.3 m size particles are produced and their concentration is strongly influenced by the welding material, type of welding and suction. The particles are amorphous in terms of morphology and contain manganese, iron and silicon, which can cause neurodegenerative diseases. Furthermore, the results indicate the importance of monitoring oral exposure.

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