The research presented in this thesis provides a quantitative analysis of atmospheric influences on particulate matter pollution in Christchurch across a wide range of spatial and temporal scales. A complex interaction of low level flow characteristics that form in response to local and regional features of complex terrain, together with an urban setting that is characterised by low density housing, mostly comprised of single storey dwellings that are poorly insulated, regularly leads to nocturnal smog events during winter in Christchurch. Provided synoptic flow is weak, the above mentioned flow interaction promotes flow stagnation over the city, when nocturnal katabatic drainage flows and day-time north-easterly on-shore winds converge over the city. Additionally, undercutting of the density currents promotes highly stable atmospheric stratification close to the surface, so that, in combination, both horizontal and vertical air movement is suppressed. As particulate emission release from solid fuel burning for home heating coincides with this poor atmospheric dispersion potential, particle concentrations can increase substantially so that national air quality guidelines are regularly exceeded during winter in Christchurch. At the core of this thesis is a classification based approach that examines the day-to-day probabilities of breaches of the national air quality guideline for PM over the last decade at a single location in Christchurch as a result of variations in meteorological conditions alone. It is shown that, based on variations in temperature and wind speed, up to 85% of exceedence occurrence can be explained. From this, concentration trends over time, when meteorological variability is kept to a minimum, are assessed and evidence is found that recent regulatory measures to enhance air quality are beginning to show positive effects. Atmospheric processes that control pollution dispersion on the mesoscale are investigated through means of atmospheric numerical modelling in a novel approach that assimilates observational climatic wind field averages to drive low level flow for two idealised case studies. It is shown that this approach is able to reproduce the observed diurnal concentration patterns very well and that much of these patterns can be attributed to mesoscale circulation characteristics and associated atmospheric dispersion potential, namely flow stagnation and recirculation of contaminants. When timing of stagnation and subsequent recirculation is such that it occurs within a few hours after peak emission release, concentration increase is enhanced and dilution is delayed, thus severely exacerbating the problem. Links between exceedence probabilities and synoptic situations that favour the degradation of air quality are established and various synoptic transition scenarios are examined with regard to local air quality. The progression of anticyclones across the country is identified to be the dominant synoptic control mechanism and it is shown that latitudinal variation in the progression path determines the extent of expected exceedence probability. On interdecadal hemispheric scales, it is found that a particular combination of local and synoptic atmospheric conditions that favours air quality degradation, shows a re-occurring pattern of frequency maxima (and minima) with a periodicity of approximately 14 - 16 years. For the synoptic part of this interdecadal variability, a close relationship to Southern Hemispheric pressure anomalies in high latitudes is revealed. Finally, for verification of the combined findings and to assess their prediction capability, a validation case study is given which shows that the applied methodology is able to capture day-to-day variations in pollution levels with acceptable (statistically significant) accuracy.

Abstract Objective: In Christchurch there is concern that winter air pollution, dominated by particulate matter (PM₁₀) from domestic heating, causes a local increase in cases of cardiorespiratory disease. Our aim was to investigate whether the particulate levels did influence emergency hospital admissions, and if so to what extent. Method: Air pollution and meteorological data was obtained from a Canterbury Regional Council monitoring station. Two local hospitals provided data on emergency admissions for both adults and children with cardiac and respiratory disorders. All data was obtained for the period from June 1988 to December 1998. Missing PM₁₀ data was interpolated from other known pollution values when necessary. The PM₁₀ data was compared to the admissions data using a time series analysis approach, with weather variables controlled for using a generalised additive model. Results: There was a significant association between PM₁₀ levels and cardiorespiratory admissions. For children and adults combined there was a 3.4% increase in respiratory admissions for every interquartile (14.8 µg/m³) increase in PM₁₀. In adults there was a 1.3 % increase in cardiac admissions for each interquartile increase in PM₁₀. There was no relationship between PM₁₀ levels and appendicitis, the condition that we selected to be our control. Conclusion: In Christchurch there is a significant relationship between particulate levels and the admissions for cardiac and respiratory illnesses. The size of the effect is comparable to other international studies, and the greatest impact is seen on the respiratory system.

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.