Dissertation (Ph.D.)--University of South Florida, 2005. / Includes vita. Title from PDF of title page. Document formatted into pages; contains 99 pages. Includes bibliographical references.

Η μελέτη της παρουσίας των αιωρούμενων σωματιδίων στην ατμόσφαιρα είναι μεγάλης σημασίας, καθώς η εκτίμηση των επιπτώσεών τους στον άνθρωπο και στο περιβάλλον είναι ένα εξαιρετικά πολύπλοκο ζήτημα για την παγκόσμια επιστημονική κοινότητα. Η μελέτη των αιωρούμενων σωματιδίων αποτέλεσε ερευνητικό αντικείμενο μόλις τις τελευταίες πέντε δεκαετίες και με βάση μελέτες που έγιναν, διαπιστώθηκε η επίπτωσή τους στην υγεία του ανθρώπου και την κλιματική αλλαγή. Επίσης, αποδεικνύεται ο ρόλος τους στις διεργασίες σχηματισμού των νεφών και της ομίχλης και στη διαμόρφωση του ενεργειακού ισοζυγίου του πλανήτη. Ωστόσο, τα αιωρούμενα σωματίδια δεν μπορούν να μελετηθούν εύκολα εξαιτίας του μικρού μεγέθους και της σύνθετης χημικής τους σύνθεσης. Σκοπός αυτής της διπλωματικής - ερευνητικής εργασίας είναι η εκτίμηση της ατμοσφαιρικής κατάστασης στο κέντρο της Πάτρας. Η εκτίμηση αυτή θα προκύψει από τη μέτρηση των συγκεντρώσεων των αιωρούμενων σωματιδίων, στο κέντρο της πόλης. Οι μετρήσεις έγιναν σε κεντρικές αρτηρίες της πόλης, ενώ συλλέχθηκαν και στοιχεία μετεωρολογικών παραμέτρων, ώστε να μελετηθεί η επίδρασή τους στις συγκεντρώσεις των αιωρουμένων σωματιδίων. Το καινοτόμο στοιχείο της διπλωματικής αυτής εργασίας είναι το γεγονός ότι έγιναν καταγραφές και για τις συγκεντρώσεις των αιωρούμενων σωματιδίων PM 1, για τα οποία δεν έχει θεσμοθετηθεί όριο επικινδυνότητας. Παρόλα αυτά, οι επιστήμονες θεωρούν ότι λόγω της μικρής διαμέτρου τους είναι πιθανό να εισχωρούν έως και το κυκλοφορικό σύστημα των ανθρώπων, με αποτέλεσμα οι επιπτώσεις τους στην υγεία του ανθρώπου να θέλει περαιτέρω διερεύνηση. Επιπρόσθετα, σε αυτήν την εργασία έγιναν μετρήσεις για την συγκέντρωση του μονοξειδίου του άνθρακα (CO) στις ίδιες τοποθεσίες και την ίδια χρονική στιγμή που έγιναν οι μετρήσεις για τα αιωρούμενα σωματίδια. Αυτό μας δίνει τη δυνατότητα να γίνει συσχετισμός των στοιχείων αυτών που καταγράφηκαν και να βγάλουμε συμπεράσματα για την ποιότητα της ατμόσφαιρας. Τέλος δε, θα γίνει σύγκριση της κατάστασης που επικρατεί στη Πάτρα με τη κατάσταση που επικρατεί σε άλλες πόλεις της Ελλάδας, καθώς και με τα όρια εκπομπής αιωρούμενων σωματιδίων, όπως αναφέρονται στη σχετική κατευθυντήρια οδηγία της Ευρωπαϊκής Ένωσης περί εκπομπής ρύπων. / The study of the presence of particulate matter in the atmosphere is of essential importance, as the estimation of particulate matter 's consequences on human and the environment is an exceptionally complex matter for the world scientific community. The study of particulate matter has been object of investigation just for the latest five decades and according several studies it has been notified the implications on human health and climate changes. It also has been proved their role in formation processes of clouds and fog and the formation of energy balance of the planet. However, particulate matters cannot be easily studied because of their very small size and their complex chemical composition. The main purpose of this diploma thesis is the evaluation of the atmospheric situation in the city of Patras. This evaluation will be resulted out of the measurement of the concentration of particulate matter at city center. The measurements have been taken from central drive arteries of the city, while have been collected also features of meteorological parameters, in order to study their effect on the concentrations of particulate matter. The innovation of this diploma thesis is the fact that there have been recorded also the concentrations of particulate matter PM1, for which there has not yet been any establishment of danger limits. Nevertheless, scientists consider that because of their very small diameter it is possible to penetrate into the human circulatory system, resulting consequences in human health, for which is needed further investigation. In addition in this diploma thesis have been reordered measurements of the concentration of carbon monoxide (CO) at the same locations and simultaneously with the particulate matter. This enables us to correlate these elements and make conclusions about the quality of the atmosphere. Finally, there will be a comparison of the situation of the air quality between Patras and other Greek cities, as well as the limits of particulate matter emission, as they refer in the relevant guidance instructions of European Community about pollutant emissions. In addition in this diploma thesis have been reordered measurements of the concentration of carbon monoxide (CO) at the same locations and simultaneously with the particulate matter. This enables us to correlate these elements and make conclusions about the quality of the atmosphere. Finally, there will be a comparison of the situation of the air quality between Patras and other Greek cities, as well as the limits of particulate matter emission, as they refer in the relevant guidance instructions of European Community about pollutant emissions.

106f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-04-03T15:25:41Z No. of bitstreams: 1 TESE FINAL DOC.pdf: 4610258 bytes, checksum: 3ecdb7656f48c692cf6c27ab84dec013 (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-04-23T15:52:10Z (GMT) No. of bitstreams: 1 TESE FINAL DOC.pdf: 4610258 bytes, checksum: 3ecdb7656f48c692cf6c27ab84dec013 (MD5) / Made available in DSpace on 2013-04-23T15:52:10Z (GMT). No. of bitstreams: 1 TESE FINAL DOC.pdf: 4610258 bytes, checksum: 3ecdb7656f48c692cf6c27ab84dec013 (MD5) Previous issue date: 2011 / CNPQ / Atualmente, um dos maiores problemas mundiais é a poluição atmosférica, oriunda essencialmente de fontes antrópicas. Os grandes impactos ambientais, como a degradação da qualidade do ar, são resultados dos processos de desenvolvimento urbano e industrial. O material particulado (MP) tem sido alvo de vários estudos devido aos efeitos nocivos causados ao meio ambiente e a saúde humana. O arsênio, um metalóide que apresenta características tanto de metal como de não-metal, é considerado altamente tóxico. A associação do arsênio ao material particulado pode provocar sérios danos à saúde da população. Os níveis de toxicidade do arsênio são dependentes de sua forma química. As espécies inorgânicas de arsênio, arsenito (AsIII) e arseniato (AsV), são também consideradas agentes carcinogênicos. O Recôncavo Baiano é uma região que apresenta grande importância ambiental, social e econômica para o estado da Bahia. Nesta área encontram-se portos, terminais marítimos e diversos pólos industriais que são as principais fontes de emissão de poluentes para o meio ambiente. O presente trabalho teve por objetivo verificar a concentração do arsênio presentes tanto nas partículas finas, quanto nas partículas grossas do material particulado atmosférico do Recôncavo Baiano, para avaliar as contribuições deste poluente à saúde da população exposta. A determinação de arsênio em material particulado, utilizando a digestão, com HNO3, e a técnica de espectrometria de fluorescência atômica acoplada à geração de hidreto (HG-AFS), mostrou-se eficiente para a matriz estudada com limite de detecção e quantificação de 0,3 ng m-3 e 1 ng m-3, respectivamente. As concentrações médias de arsênio, obtidas no material particulado em algumas regiões do Recôncavo Baiano, estavam em torno de 30 ng m-3, valor cinco vezes maior que o recomendado pela União Européia (6 ng m-3). O arsênio presente no material particulado encontra-se substancialmente nas partículas finas. Alertando para os riscos de exposição da população, nos municípios onde foram feitas as amostragens. Os resultados apresentados neste trabalho são indicativos da necessidade de se atualizar os padrões de qualidade do ar para o Brasil, incluindo outros poluentes como o arsênio / Salvador

abstract: Americans spend upwards of 90% of their time indoors, hence indoor air quality (IAQ) and the impact of IAQ on human health is a major public health concern. IAQ can be negatively impacted by outdoor pollution infiltrating indoors, the emission of indoor pollutants, indoor atmospheric chemistry and poor ventilation. Energy saving measures like retrofits to seal the building envelope to prevent the leakage of heated or cooled air will impact IAQ. However, existing studies have been inconclusive as to whether increased energy efficiency is leading to detrimental IAQ. In this work, field campaigns were conducted in apartment homes in Phoenix, Arizona to evaluate IAQ as it relates to particulate matter (PM), carbonyls, and tobacco specific nitrosamines (TSNA). To investigate the impacts of an energy efficiency retrofit on IAQ, indoor and outdoor air quality sampling was carried out at Sunnyslope Manor, a city-subsidized senior living apartment complex. Measured indoor formaldehyde levels before the building retrofit exceeded reference exposure limits, but in the long term follow-up sampling, indoor formaldehyde decreased for the entire study population by a statistically significant margin. Indoor PM levels were dominated by fine particles and showed a statistically significant decrease in the long term follow-up sampling within certain resident subpopulations (i.e. residents who reported smoking and residents who had lived longer at the apartment complex). Additionally, indoor glyoxal and methylglyoxal exceeded outdoor concentrations, with methylglyoxal being more prevalent pre-retrofit than glyoxal, suggesting different chemical pathways are involved. Indoor concentrations reported are larger than previous studies. TSNAs, specifically N'-nitrosonornicotine (NNN), 4-(methyl-nitrosamino)-4-(3-pyridyl)-butanal (NNA) and 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK) were evaluated post-retrofit at Sunnyslope Manor. Of the units tested, 86% of the smoking units and 46% of the non-smoking units had traces of at least one of the nitrosamines. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2014

Submitted by HENDRYK GEMEINER null (h.gemeiner@gmx.net) on 2016-11-11T17:05:34Z No. of bitstreams: 1 tese_mestrado_hendryk_gemeiner.pdf: 13978829 bytes, checksum: 08b385f98431fd9c29309e3aeb7cb1b2 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-11-11T17:52:30Z (GMT) No. of bitstreams: 1 gemeiner_h_me_rcla.pdf: 13978829 bytes, checksum: 08b385f98431fd9c29309e3aeb7cb1b2 (MD5) / Made available in DSpace on 2016-11-11T17:52:30Z (GMT). No. of bitstreams: 1 gemeiner_h_me_rcla.pdf: 13978829 bytes, checksum: 08b385f98431fd9c29309e3aeb7cb1b2 (MD5) Previous issue date: 2016-09-13 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação para o Desenvolvimento da UNESP (FUNDUNESP) / The toxic metal lead (Pb) can be harmful to human health in various manners, but is also considered as a distinguished tracer of environmental pollution, since the relative abundance of its four stable isotopes with the atomic masses of 204, 206, 207 and 208 varies with the emission source. This study is focused on the lead concentrations and isotope ratios in the particulate matter of the Brazilian cities of Goiânia (GO) and Rio Claro (SP), in order to determine the main Pb pollution sources. Particulate matter samples were collected on clean Teflon filters during the rainy and dry season between 2014 and 2016 on the campus of the State University of São Paulo (UNESP) in Rio Claro city and in the centre of Goiânia city near main roads with a high traffic volume. The Pb concentrations as well as the 206Pb/207Pb and 208Pb/207Pb stable isotope ratios of the particulate matter samples were analysed by Inductively-Coupled Plasma Mass Spectrometry. To apply this analytical technique successfully, it was necessary to optimize parameters in case of acquisition time, detector dead time and mass discrimination, which affect the measurement accuracy and precision. Results showed that lead concentrations in Goiânia were different between rainy and dry season. In Goiânia, Pb concentrations showed higher values in dry season than in rainy season, while Pb concentrations were more similar in both sampling periods in Rio Claro. Back trajectories were analysed with the HYSPLIT model to investigate associations between Pb concentration levels and the direction of incoming air masses. However, the comparison of the obtained 206Pb/207Pb and 208Pb/207Pb isotope ratios data with data of potential Pb sources from previous studies indicated that gasoline may be considered as main Pb sources in the particulate matter of Goiânia and Rio Claro. Pb isotope ratios in Goiania were slightly different between dry and rainy season, while in Rio Claro, 206Pb/207Pb isotope ratios showed markedly higher values in dry season than in rainy season. Hence, Pb in Rio Claro in dry season also seems to be influenced by industrial emissions. These assumptions were supported by the calculation of 208Pb/206Pb-207Pb/206Pb diagrams and the contribution factor of Pb coming from gasoline by applying binary mixing equations. / CNPq: 372125/2014-0 / FUNDUNESP: 0050.0092854.14.9

Neste trabalho propõe-se uma análise da dispersão de material particulado gerado por fontes estacionárias, aplicando ferramentas de Fluidodinâmica Computacional (em inglês Computatonal Fluid Dynamics, CFD), usando um modelo Euleriano para o escoamento e Lagrangeano para as partículas, em estado estacionário no software Fluent. A verificação da modelagem é apresentada em duas sessões, a primeira compreende o estudo do escoamento atmosférico em condições de estabilidade neutra incluindo os efeitos das heterogeneidades do terreno, no caso, um monte de 126m de altura em escala real. Foram comparados diferentes modelos de turbulência: padrão, RNG e parametrizado para o caso atmosférico. Os três modelos apresentaram desempenho semelhante e descrevem satisfatoriamente as tendências dos dados experimentais. A segunda, o modelo lagrangeano baseado no tempo de vida dos turbilhões (em inglês Discrete Random Walk, DRW) foi utilizado para representar a distribuição de concentrações de material particulado em um ambiente confinado. Os resultados numéricos descrevem satisfatoriamente os perfis de concentrações das partículas, porém subestimam os valores na região próxima à parede, o que indicaria que uma melhor aproximação da deposição das partículas deve ser considerada. Após estes estudos, esta abordagem euleriana-lagrangeana foi aplicada ao caso da dispersão de material particulado em condições de atmosfera neutra em uma região do Polo Cerâmico de Santa Gertrudes-SP, local responsável pela maior produção de revestimentos cerâmicos do Brasil. O trânsito de caminhões nas estradas não pavimentadas foi identificado como fonte de material particulado que atinge o perímetro urbano da cidade. Estudaram-se também as contribuições das atividades referentes à exploração das minas de argila e a preparação do solo para uso agrícola, apesar desta última não soma uma carga relevante ao ser comparada com as duas anteriores. Além da influência das fontes mencionadas, fontes de origem industriais localizadas dentro da cidade também foram consideradas no cenário. / In this study an analysis of the dispersion of particulate matter generated by stationary sources is proposed, by applying Computational Fluid Dynamics (CFD) tools, using an Eulerian model for the flow and a Lagrangean model for the particles, under steady-state conditions in the Fluent software. The model validation is presented in two sessions, the first comprises the study of the atmospheric flow under conditions of neutral stability, including the effects of the heterogeneities of the terrain. In this case, the air flow past a 126m high hill in real scale was adopted. Different turbulence models were compared: standard k-?, k-? RNG and parametrized k-?. The three models presented similar performance and described satisfactorily the trends of the experimental data. Subsequently, the Lagrangean model based on the Eddy life time (DRW - Discrete Random Walk) was used to represent the distribution of particulate matter concentrations in a confined environment. The numerical results satisfactorily describe the particle concentration profiles, but underestimate the values in the region near the wall, which would indicate that a better approximation of the particle deposition should be considered. After these studies, this Eulerian- Lagrangean approach was applied to the case of dispersion of particulate material under neutral atmosphere conditions in a region around the city of Santa Gertrudes-SP, where the Ceramic Complex is responsible for the largest production of ceramic tiles in Brazil. Transit of trucks on unpaved roads has been identified as a source of particulate matter that reaches the urban perimeter of the city. The contributions of the activities related to mining and the preparation of the soil for agricultural use were also studied, although this last one does not add a significant load when compared with the two previous ones. In addition to the influence of the mentioned sources, industrial sources located inside the city also contribute to the scenario.

O presente trabalho avaliou a qualidade do ar de uma área central da cidade de São Carlos-SP, mais precisamente no campus 1 da Universidade de São Paulo. Nessa região há grande movimentação de pessoas e veículos, principalmente durante o horário comercial. Esta avaliação foi feita com base na determinação de um dos parâmetros utilizados para verificar a qualidade do ar, o material particulado (MP) inalável em suspensão, ou seja, partículas que possuem diâmetro aerodinâmico menor ou igual a 10 μm e podem penetrar no sistema respiratório, sendo portanto, nocivas à saúde humana. O MP foi determinado em suas frações de 2,5 e 10 μm de diâmetro (MP10 e MP2,5). Duas metodologias diferentes foram utilizadas para determinar a concentração do material particulado em suspensão, fotometria por espalhamento de luz, através do equipamento ADR-1500 e gravimetria, através do PEM (Personal Enviromental Monitor). Os valores obtidos pelo método gravimétrico foram superiores aos resultados encontrados através da fotometria. As concentrações obtidas foram comparadas com os limites recomendados pela Organização Mundial da Saúde para o MP em suas frações de 2,5 e 10 μm, iguais respectivamente a 25 e 50 μg/m3. Além do material particulado foram obtidos dados para temperatura, umidade relativa e precipitação. As médias obtidas para as concentrações de MP10 e MP2,5, com o método gravimétrico, o qual fornece os resultados mais confiáveis, foram iguais respectivamente a 48,8 e 23,1 μg/m3, muito próximas portanto, de seus limites correspondentes. As menores concentrações obtidas para o MP10 foram, em sua maioria, verificadas em dias chuvosos, tanto através do PEM como do ADR. As concentrações de MP2,5, obtidas somente através do PEM, também apresentaram os menores valores em dias com chuva. Foi desenvolvido um modelo matemático que prevê o comportamento do MP10 durante as precipitações, evento este que se mostrou o mais importante na influência da concentração de material particulado atmosférico. / This study evaluated the air quality of a central area of the city São Carlos-SP, more precisely on the Campus 1 of the University of São Paulo. In this region there is a large movement of people and vehicles, manly during business hours. This evaluation was made based on determination of one parameter used to verify air quality, the inhalable particulate material (PM) suspended in the air, in other words, particles which have aerodynamic diameter less or equal to 10 μm and can penetrate in the respiratory system, therefore, harmful to human health. The PM was determined in its fractions from 2,5 and 10 μm of diameter (PM10 e PM2,5).). Two different methodologies were used to determinate the concentration of particulate suspended material, photometry by scattered light, using the equipment ADR-1500, and gravimetry, thru PEM (Personal Environmental Monitor). The data obtained from gravimetry were higher than the results found thru photometry. The concentrations found were compared to the limits recommended by World Health Organization for PM and its fractions of 2,5 and 10 μm, equal to 25 and 50 μg/m3. Besides PM, temperature, relative humidity and precipitation were measured. The average values for the concentrations of PM10 and PM2,5 , using gravimetry, which provide more reliable results, it were equal to 48,8 and 23,1 μg/m3, therefore really close to their corresponding limits. The lower concentrations seen for PM10 were, mostly, verified on rainy days, using PEM and ADR. The concentrations of PM2,5 , obtained just using PEM, also had the lowest values during rainy days. A mathematical model was developed to predict PM10 behavior during precipitations, this event has shown to have the most important influence on the concentration of atmospheric particulate matter.

Increased exposure to ambient particulate matter (PM) is associated with elevated morbidity and mortality in patients with cardiopulmonary diseases and cancer. We and others have shown that PM induces lung microvascular barrier dysfunction which potentially enhances the systemic toxicity of PM. However, the mechanisms by which PM disrupts vascular endothelial integrity remain incompletely explored. We hypothesize that PM induces endothelial cell (EC) cytoskeleton rearrangement via Rho GTPase-dependent pathways to facilitate vascular hyperpermeability. Fine PM induced time-dependent activation of cytoskeletal machinery with increases in myosin light chain (MLC) phosphorylation and EC barrier disruption measured by transendothelial electrical resistance (TER), events attenuated by the Rho-dependent kinase (ROCK) inhibitor Y-27632 or the reactive oxygen species (ROS) scavenger, N-acetylcysteine (NAC). Both Y-27632 and NAC prevented PM-induced stress fiber formation and phospho-MLC accumulation in human lung ECs. PM promotes rapid accumulation of Rho-GTP. This event is attenuated by NAC or knockdown of RhoA (siRNA). Consistent with ROCK activation, PM induced phosphorylation of myosin light chain phosphatase (MYPT) at Thr850, a post-translational modification known to inhibit phosphatase activity. Furthermore, PM activates the guanine nucleotide exchange factor (GEF) for Rho, p115, with p115 translocation to the cell periphery, in a ROS-dependent manner. Together these results demonstrate that fine PM induces EC cytoskeleton rearrangement via Rho-dependent pathways that are dependent upon the generation of oxidative stress. As the disruption of vascular integrity further contributes to cardiopulmonary physiologic derangements, these findings provide pharmacologic targets for prevention of PM-induced cardiopulmonary toxicity.

In the United States, approximately 3% of infants are diagnosed with a major birth defect each year. Whereas prevention efforts have led to decreases in some birth defects, the cause of approximately 70% of birth defects remains unknown. More recently, there has been increasing concern regarding exposures to environmental agents, such as air pollution during pregnancy, and the risk of birth defects. Over the past decade, there has been an increase in research studies examining the association between air pollution and birth defects. The results have been inconsistent, with some studies reporting that higher levels of exposure from the same pollutant increase the risk of birth defects, whereas others report no risk or even a decrease in risk. These inconsistencies may arise from differences in exposure assessment methods across epidemiological studies. A comprehensive series of sensitivity analyses were conducted to evaluate the impact of different exposure estimation decisions on the adjusted measures of associations between ambient air pollution exposure and birth defects. For each of six decisions – spatial scale, spatial limit, temporal scale, temporal limit, data aggregation sequence, and weighting scheme – two alternative choices were considered, and maternal exposure to PM2.5 and benzene were estimated for each ‘sensitivity case' (unique combination of choices across all decisions). For each sensitivity case, adjusted prevalence ratios (aPRs) and 95% confidence intervals (CI) were estimated from multivariable regression models comparing each exposure quartile to the first quartile; each measure of association represented the associations between either benzene or PM2.5 and one of the birth defects under study. To then evaluate the impact of selecting alternative choices for each exposure assessment decision, three metrics were used: 1) the percent difference in the aPR point estimates between alternative choices for a specific decision (calculated for each sensitivity case pairing); 2) the percent of sensitivity cases in which the aPR 95% CIs for alternative choices for a specific decision overlapped (i.e., were not statistically significantly different); and 3) the percent of sensitivity cases in which there was agreement in the substantive conclusion of the association between exposure (pollutant) and outcome (defect), the conclusion being either statistically significant increased risk, statistically significant decreased risk, or no statistically significant difference in risk. Second, a retrospective cohort study was conducted to investigate the association between maternal exposure to ambient benzene and PM2.5 and the risk of musculoskeletal birth defects in offspring. For both analyses, data on singleton infants born from 2000 to 2013 were obtained from the Florida Birth Defects Registry and air pollution data were obtained from the Environmental Protection Agency Air Quality System database. Exposure estimates were calculated for all birth defect cases and non-affected births during etiologically relevant time windows and multivariable regression models were used to obtain aPRs and 99% CIs comparing each quartile of exposure to the first. For PM2.5, across all exposure-outcome pairs under study, the alternative choices for the decision of spatial scale resulted in the largest median percent difference in aPRs (e.g., between county and block group) when results were aggregated for all quartiles. This was followed by the temporal scale and spatial limit decisions. For benzene, spatial limit resulted in largest median percent difference in aPRs, followed by spatial scale and temporal scale. However, for both pollutants, when evaluating the agreement in aPRs between alternative choices on the direction and significance of the association (i.e., statistically significant increase, decrease, or no risk), the decision of spatial limit resulted in the lowest percent agreement (biggest impact). Temporal limit had the second lowest percent agreement for PM2.5, whereas spatial scale had the second lowest for benzene. Finally, the metric assessing the level of overlap in 95% CIs for the measures of association was inconsequential, suggesting little impact of any exposure assessment decision, and doing little to differentiate between the relative impacts of each decision. That is because, for all exposure-outcome pairs, when comparing alternative choices for each decision, there was 100% overlapping intervals (i.e., no aPRs were statistically significantly different from each other). Lastly, exposure assessment decisions impacted the analytic sample sizes, with some decisions resulting in a three-fold difference in the sample size alone. Mothers of singleton infants exposed to higher levels of ambient PM2.5 were more likely than mothers with lower exposure levels to give birth to an infant with isolated anomalies of the skull and face bones, any rib and sternum anomalies, any skull and face anomalies, any spine anomaly, and other congenital anomalies of lower limb including pelvic girdle. Higher PM2.5 exposure was also associated with an increased risk of non-isolated anomalies of skull and face bones, any skull and face anomalies, and reduction deformities of the upper limb. Exposure to higher levels of benzene was associated with an increased risk of isolated congenital hip dislocation and congenital valgus deformities of feet as well as multiple inverse associations. The findings presented here indicate that measures of association between maternal pollutant exposures (PM2.5 and benzene) and selected birth defect outcomes in offspring are sensitive to exposure assessment decisions, with some decisions more impactful than others. The findings can be used, not only to explain the lack of consistency in results across existing epidemiological studies, but to guide decision-making in future studies. This study also adds to the growing body of epidemiological studies suggesting an association between specific air pollutants and birth defects. In the current political climate, it is important that researchers continue to provide evidence of the detrimental health effects of air pollution in order to circumvent change in current policies established to regulate and reduce pollution emissions.

When inhaled, bioaerosols exacerbate respiratory symptoms and diseases. Mitigating the negative health impacts of bioaerosols requires a robust understanding of the temporal and spatial dynamics of bioaerosols in the atmosphere as a function of their type (e.g., bacteria, fungal spores, plant pollens) and particle size, which determines their penetration into the respiratory tract. While it is known that bioaerosol concentrations vary by location, season and meteorological conditions, major gaps remain in understanding the co-occurrence of bioaerosols with one another, their size in the atmosphere, and their mass contributions to PM. Overall, research presented in this thesis advances the current knowledge about bioaerosols (including fungal spores, pollens, and bacteria) in following ways: 1) defining background and urban levels of bioaerosol concentrations in the Midwestern US across four seasons, 2) characterizing ambient bioaerosol and co-pollutant mixtures, 3) determining the influence of meteorology on their concentrations and size distributions, and 4) estimating bioaerosol contributions to PM mass. The spatial analysis of respirable particulate matter (PM10) across urban and background sites in Iowa demonstrated that urban areas are a source of fungal glucans, bacterial endotoxins and total proteins, which gives rise to significantly enhanced bioaerosols in urban locations compared to background sites. Similar urban enhancements in calcium—a crustal element—and its correlation with endotoxins suggested that wind-blown soil is likely the origin. Seasonally, fungal spores peaked in summer with temperature, while bacterial endotoxins peaked in autumn during the row crop harvesting season. Fungal spores, bacterial endotoxins, plant and animal detritus all peaked during the growing season, such that maximum exposures to multiple bioaerosol types concurrently. Under the influence of rain chemical tracers of pollens peaked and decreased in size from coarse (2.5-10 µm) to fine particles (< 2.5 µm), likely due to the osmotic rupture of pollen grains upon wetting. While fine-sized fungal spores also increased during rain events, maximum spore levels were observed in coarse-sized particles post-rain. The comparison of spring to late summer measurements demonstrated these influences of precipitation on bioaerosols also occur during late summer, when fungal spore levels are high and ragweed is the dominant pollen source. The ability to apportion PM mass to bioaerosols was advanced through the development of chemical profiles of pollens and their integration with chemical mass balance (CMB) source apportionment modeling, for the first time. In late-April to early-May in 2013, pollens were estimated to contribute 0.2 - 38% of PM₁₀ (0.04 – 0.8 µg m⁻³) while fungal spores contributed 0.7 – 17% of PM₁₀ (0.1 – 1.5 µg m⁻³). Collectively, this thesis provides insight into spatial, seasonal and daily variations of bioaerosols, and shows elevated outdoor exposures to bioaerosols among urban populations, with maximum levels occurring during growing seasons, periods of high temperature, and during/immediately following rainfall.