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Estudo crítico de métodos de preparo de amostras de material particulado atmosférico para determinação de elementos-traço por espectrometria de absorção atômicaMimura, Aparecida Maria Simões 23 March 2017 (has links)
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Previous issue date: 2017-03-23 / Na atmosfera são encontradas partículas de sólidos ou líquidos que se encontram suspensas no
ar, chamadas de particulados. O tamanho dessas partículas pode estar associado ao seu
potencial para causar danos à saúde humana, uma vez que estas podem ficar retidas no trato
respiratório, desencadeando diversas doenças. Na superfície do material particulado podem
ser encontrados, entre diversos contaminantes, os elementos-traço. Neste contexto, o objetivo
deste estudo foi desenvolver métodos analíticos para a extração de elementos-traço em
amostras de material particulado atmosférico com posterior determinação destes elementos
por espectrometria de absorção atômica. As amostras foram coletadas mensalmente na cidade
de Juiz de Fora, MG, Brasil, num período de 24 meses, utilizando coletores passivos
instalados em quatro pontos de coleta (em duas avenidas com intenso fluxo de veículos, em
uma área industrial e em uma região com elevada altitude e menor tráfego de veículos). Os
parâmetros instrumentais para a determinação de Al, As, Cd, Cr, Cu, Fe, Mn, Pb e Zn por
espectrometria de absorção atômica com chama (F AAS) e espectrometria de absorção
atômica com forno de grafite (GF AAS) foram investigados. Dois métodos de preparo de
amostras de material particulado foram desenvolvidos, utilizando extração assistida por
ultrassom e extração assistida por micro-ondas. Os métodos apresentaram resultados
adequados referentes à precisão (RSD <10 %) e à exatidão (recuperações entre 83 e 114 %),
tempo reduzido (10 min) no preparo das amostras e pequeno consumo de reagente (água
régia: 5,0 mL). As amostras de material particulado (n = 92) foram preparadas com o método
de extração assistida por micro-ondas utilizando água régia diluída, com posterior
determinação dos analitos por F AAS e GF AAS. Utilizando o cálculo do fator de
enriquecimento, a análise de componentes principais, a análise de agrupamentos hierárquicos
e a matriz de correlação de Pearson, foram identificadas as possíveis fontes de cada analito
em cada ponto. Os analitos Al, Fe, Cr e Mn foram relacionados a fontes naturais, como a
ressuspensão de poeira do solo. No entanto, os analitos As, Cu, Cd, Pb e Zn podem estar
associados a fontes antrópicas. Valores médios elevados foram obtidos para Cd, Pb e Zn (146,
2895, 40924 mg kg-1, respectivamente) no ponto 2, região com intensa atividade industrial.
De modo geral, as possíveis fontes dos analitos nas amostras de material particulado
estudadas são ressuspensão de poeira do solo, poluição industrial (metalurgia e siderurgia),
queima de biomassa, construção civil e queima de combustíveis fósseis. / On the atmosphere, particles of solids or liquids are found, suspended in the air, known as
particulate matter. The size of these particles may be associated with their harmful potential to
human health, since they can be retained in the respiratory tract, causing several diseases.
Several contaminants, such as trace elements, can be found on the surface of particulate
matters. In this context, the aim of this study was to develop analytical methods for extraction
of trace elements from atmospheric particulate matter samples with subsequent determination
of these elements by atomic absorption spectrometry. The samples were collected, monthly, in
the city of Juiz de Fora, MG, Brazil, during 24 months, using passive samplers, installed at
four sampling sites (two avenues with large fleet of vehicles, an industrial area and a region
with high altitude and small fleet of vehicles). Instrumental parameters for the determination
of Al, As, Cd, Cr, Cu, Fe, Mn, Pb and Zn by flame atomic absorption spectrometry (F AAS)
and graphite furnace atomic absorption spectrometry (GF AAS) were investigated. Two
sample preparation methods for particulate matters were developed, using ultrasonic assisted
extraction and microwave assisted extraction. The methods showed adequate results regarding
precision (RSD <10 %) and accuracy (recoveries between 83 and 114 %), with reduced time
(10 min) in sample preparation and low reagent consumption (aqua regia: 5.0 mL). Particulate
matter samples (n = 92) were prepared with microwave assisted extraction using diluted aqua
regia, with subsequent determination of the analytes by F AAS and GF AAS. Using
enrichment factor, principal component analysis, hierarchical cluster analysis and Pearson
correlation, the possible sources of each analyte at each point were identified. The analytes
Al, Fe, Cr and Mn were related to natural sources, such as the resuspension of soil dust.
However, the analytes As, Cu, Cd, Pb and Zn may be associated with anthropogenic sources.
Critical mean values were obtained for Cd, Pb and Zn (146, 2895, 40924 mg kg-1,
respectively) at site 2, a region with intense industrial activity. In general, the possible sources
of the analytes in the studied particulate matter samples are resuspension of soil dust,
industrial emission (metallurgy and steel mill), biomass burning, building construction and
fossil fuel emissions.
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[en] STUDY OF THE CHEMICAL COMPOSITION OF THE SUSPENDED PARTICULATE MATTER IN THE AIR IN RIO DE JANEIRO CITY / [pt] ESTUDO DA COMPOSIÇÃO QUÍMICA DO MATERIAL PARTICULADO EM SUSPENSÃO NO AR NA CIDADE DO RIO DE JANEIRODANIELA SILVEIRA SOLURI 27 October 2005 (has links)
[pt] Dez amostradores de material particulado em suspensão no
ar foram
instalados em diferentes bairros da cidade do Rio de
Janeiro: Gávea, Honório
Gurgel, Jacarepaguá, Campo Grande, Tijuca, Ilha do Fundão,
Guaratiba,
Recreio dos Bandeirantes, Santa Cruz e Realengo, visando
contribuir para um
maior entendimento a respeito da poluição atmosférica na
cidade. Os
amostradores empregados foram desenvolvidos pela
Universidade de Gent e
permitem a coleta das frações inalável (com diâmetro
aerodinâmico entre 2,5 e
10µm, MP2,5-10) e respirável (com diâmetro aerodinâmico
< 2,5 um, MP2,5). As
amostragens foram realizadas, simultaneamente, sempre no
meio da semana,
durante 24 horas, e compreenderam o período de
setembro/2003 a
setembro/2004. Ao final deste período, foram obtidas, por
ponto de
amostragem, trinta amostras de cada fração, totalizando
seiscentas amostras.
Após a determinação da massa presente em cada filtro, e do
teor de carbono
elementar no filtro fino (MP2,5), os filtros foram
divididos em duas partes. Numa
delas foi determinada a concentração de amônio, sódio,
potássio, cálcio,
magnésio, cloreto, nitrato e sulfato solúvel em água e, na
outra parte, a
concentração de sódio, potássio, cálcio, magnésio,
alumínio, ferro e titânio
após dissolução total. A estação de Honório Gurgel foi
aquela que apresentou,
na média, as maiores concentrações de carbono elementar,
particulado grosso
e total, refletindo a proximidade com a Avenida Brasil e a
presença de
indústrias na região. O ponto de coleta com maior
concentração de particulado
fino e de aerossol de origem secundária correspondeu
àquele localizado na
Ilha do Fundão, próximo a bairros com uma grande
concentração de indústrias,
como Bonsucesso e São Cristóvão, além de vias expressas,
como a Linha
Vermelha e a Avenida Brasil. Por outro lado, as estações
de amostragem
localizadas no Recreio dos Bandeirantes e em Guaratiba
apresentaram as
menores concentrações de particulado fino, grosso e de
carbono elementar. Os
parâmetros analisados permitiram identificar cerca de 70%
da origem do
material presente nas frações fina e grossa do material
particulado em
suspensão no ar nas regiões estudadas da cidade do Rio de
Janeiro. Como
esperado, o particulado grosso é, em grande parte, oriundo
da ressuspensão do solo, contendo, ainda, aerossol marinho
e compostos de origem secundária,
como sulfato e nitrato. O particulado fino, por sua vez, é
majoritariamente
oriundo da combustão de combustíveis fósseis que dão
origem ao aerossol
secundário e ao carbono elementar, possuindo uma
contribuição de origem
terrígena e de aerossol marinho. / [en] The present work intend to be a contribution for the
understanding of the
air pollution in the Rio de Janeiro city, aerosol sampling
was performed at ten
different sites of the city: Gávea, Honório Gurgel,
Jacarepaguá, Campo Grande,
Tijuca, Ilha do Fundão, Guaratiba, Recreio dos
Bandeirantes, Santa Cruz and
Realengo. Stacked filter units (SFU), developed by Gent
University, were used
as samplers. These filters separate the particles into two
main fractions: the fine
mode defined as respirable particles (with aerodynamic
diameter < 2.5 um,
PM2.5), and coarse mode defined as inhalable particles
(with aerodynamic
diameter between 2.5 um and 10 um, PM2.5-10). The aerosol
monitoring stations
were simultaneously operated, always in the middle of the
week, during 24 h,
from September/2003 to September/2004. At the end of this
period, 30 samples
of each fraction were obtained from each of the sampling
sites (600 filter
samples in total). After the determination of the mass
concentration, and the
elemental carbon amount present in each of the fine
filters, the filters were
divided into two parts. The first part was used to
determine the concentration of
ammonium, sodium, potassium, calcium, magnesium, chloride,
nitrate and
sulfate soluble in water and, the other one, for the
determination of the
concentration of sodium, potassium, calcium, magnesium,
aluminum, iron and
titanium. The Honório Gurgel site presented, in average,
the highest
concentration of elemental carbon, mass concentration of
coarse mode and
total particle mass concentration, which could be
explained by the proximity to
the Avenida Brasil and industries of the region. The
sampling site of the highest
concentration of the fine mode and secondary aerosol was
the one localized in
Ilha do Fundão, near industrial areas such as Bonsucesso
and São Cristóvão,
and heavy automobile traffic lines like Linha Vermelha and
Avenida Brasil. In
other hand, the sites localized at Recreio dos
Bandeirantes and at Guaratiba
presented in the smallest mass concentration of fine and
coarse mode and
elemental carbon. Based on these determined parameters, it
was possible to
identify 70% of the origin of the material present in the
fine ad coarse fractions
of the particulate matter suspended in the air in the
studied areas of Rio de
Janeiro city. As expected, the coarse mode particle came
from resuspended soil dust, together with marine aerosol
and some secondary aerosol, like nitrate
and sulfate. The fine mode particle came mainly from
fossil fuel combustion that
originates secondary aerosol and the elemental carbon,
with additional
contribution from marine aerosol and terrigineous material.
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Volatilisation des pesticides depuis les plantes : approche expérimentale et modélisation / Pesticide volatilization from plants : experimental approach and modellingLichiheb, Nebila 08 October 2014 (has links)
L’activité agricole présente la principale source de contamination de l’atmosphère par les pesticides. Les niveaux de concentration des pesticides dans l’atmosphère méritent une attention particulière de la part de la recherche compte tenu de leurs impacts potentiels sur la population et les écosystèmes. Bien que la volatilisation depuis la plante soit reconnue plus intense et plus rapide que la volatilisation depuis le sol, cette voie de transfert est à ce jour la moins bien renseignée avec peu de modèles disponibles pour sa description. Le manque de connaissances est lié essentiellement à la complexité des interactions entre les processus ayant lieu à la surface de la feuille et qui sont en compétition avec la volatilisation, notamment la pénétration foliaire et la photodégradation. Un système de chambre de volatilisation a été développé afin d’étudier d’une manière simultanée les processus de volatilisation et de pénétration foliaire. Les expérimentations réalisées avec 3 fongicides (époxyconazole, chlorothalonil et fenpropidine) appliqués sur feuilles de blé ont permis une description affinée du processus de pénétration foliaire grâce au protocole d’extraction des feuilles mis en place. Des coefficients de pénétration indispensables à la modélisation du devenir des pesticides à la surface des feuilles ont été calculés ainsi que des relations entre les propriétés physico-chimiques des pesticides et les processus qui contrôlent leur distribution sur et dans la feuille. L’étude expérimentale portant sur le processus de photodégradation a consisté en une irradiation de films de cire simulant les feuilles de blé traités avec des pesticides dans un simulateur solaire Suntest. Les résultats ont démontré que les pertes par photodégradation sont négligeables dans les conditions expérimentales et les pesticides choisis. Le modèle d’échange Sol-Végétation-Atmosphère SURFATM a été adapté aux pesticides selon une approche inspirée du modèle PEARL avec dans un premier temps des coefficients empiriques des processus de pénétration et de photodégradation. L’originalité de ce modèle réside dans sa description mécaniste des conditions micro-météorologiques à l’intérieur du couvert végétal. Ensuite, une approche de distribution des résidus de pesticides dans différents compartiments de la surface foliaire a été définie en se basant sur les résultats expérimentaux, permettant ainsi de prédire la fraction disponible à la volatilisation. La combinaison de cette approche avec les relations déduites entre les propriétés physico-chimiques des pesticides et le processus de pénétration foliaire améliore la généricité du modèle. Par ailleurs, l’effet de la formulation observé expérimentalement a été intégré via des coefficients empiriques permettant ainsi de mieux simuler les flux de volatilisation des produits systémiques. La comparaison entreles sorties du modèles et les résultats expérimentaux recueillis à partir de deux jeux de données acquis sur deux sites différents donne des résultats satisfaisants. Une fois activée la volatilisation depuis le sol, le modèle SURFATM-Pesticides permettra de prédire les émissions vers l’atmosphère de pesticides par volatilisation depuis les parcelles traitées. / The agricultural activity presents the main source of the atmospheric contamination by pesticides. The occurrence of pesticides in the atmosphere concerns the research community due to their potential impacts on population and ecosystems. The volatilization from plants is higher and faster than the volatilization from soil. However, this transfer pathway is difficult to assess with few available models. The lack of knowledge on pesticide volatilization from plants is essentially linked to the complex interactions between processes occurring at the leaf surface and competing with volatilization, such as leaf penetration and photodegradation. A laboratory volatilization chamber was developed in order to study simultaneously the processes of volatilization and leaf penetration of 3 fungicides (epoxyconazole, chlorothalonil and fenpropidine) applied on wheat leaves. These experimentations allowed a refined description of leaf penetration process using a well-defined sequential extraction procedure of leaves. Leaf penetration coefficients, which are necessary to modelling the pesticide fate in plants, were calculated. Moreover relationships between physicochemical properties of pesticides and processes regulating their distribution on and in plant leaves were identified. The experimental study on the photodegradation process consisted in irradiating wax films using simulated solarlight. The results showed that for experimental conditions and pesticides chosen in our study, photodegradation seems to have played a minor role as dissipation process.The soil-vegetation-atmosphere exchange model SURFATM was adapted for pesticides using an approach inspired from the parameterization developed in the PEARL model. The originality of this model resides in its mechanistic description of the micro-meteorological conditions inside the canopy. As a first step the SURFATM-Pesticides model describes leaf penetration and photodegradation processes using empirical coefficients. Then a distribution of pesticide residues in the different compartments of the leaf surface was identified based on the experimental results. This approach allowed the quantification of pesticide fraction on the leaf surface available for volatilization. The combination of this compartmental approach and the identified relationships between physicochemical properties of pesticides and the leaf penetration process improves the genericity of the model. Moreover, the effect of the pesticide formulation in the commercial preparations was integrated in the model via empirical coefficients allowing a better simulation of the volatilization fluxes in the case of systemic pesticides. Comparison of model results and experimental measurements collected from two datasets showed satisfactory results. Once the contribution of soil volatilization has been activated, the SURFATM-Pesticides model will allow us to predict the overall pesticide volatilization at the field scale.
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Influência dos resíduos da poluição atmosférica na saúde respiratória e qualidade de vida de motoristas de transporte coletivo urbano em uma cidade do Pontal do Paranapanema. / Influence of air pollution residues in respiratory health and quality of life of urban collective transportation drivers in a city of Paranapanema Pontal.VICENTE, Danillo Nascimento 18 December 2017 (has links)
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Previous issue date: 2017-12-18 / Introduction: Urban air pollution has been one of the biggest problems in society. In Pontal do Paranapanema there are several factors that contribute to this pollution, among them the increase in the vehicle fleet registered in Presidente Prudente, the lack of suitable places for solid waste disposal and the burning of sugarcane straw. Due to the large area of contact between the surface of the respiratory system and the environment, air quality directly interferes with respiratory health. Thus, it can cause a mucociliary dysfunction that is responsible for episodes of exacerbations, which causes hypersecretion, recurrent infections and, consequently, dyspnea. The mucociliary system is the first mechanical barrier to come into contact with these air pollutants and its integrity is fundamental for the protection of the respiratory system. Currently the most accepted concepts of quality of life aim at a multiplicity of dimensions. Objective: to evaluate the influence of air pollution residues on respiratory health and quality of life of public urban transport drivers in a city of Pontal do Paranapanema. Methodology: 30 individuals of both sexes were evaluated, divided into two groups: Control Group - GC, consisting of 10 employees from the administrative sector and the Motorists - GM Group, made up of 20 drivers who are directly exposed to pollution. Measurement of carbon monoxide from expired air (COex) was performed to evaluate the nasal mucociliary transport, the saccharine transit time test (TTS) was used. Both carried out at the beginning and end of the working day in the three moments measured. The perception of quality of life (QOL) was analyzed through the application of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), applied before the beginning of the working day on the first day of evaluation. Results: The results of the TTS test for the group drivers showed increased transport speed from the first to the third day of research. Already the perception of QoL was observed that in the pain domain was higher for the Workers of the Control Group (p <0.05). Conclusion: Exposure to air pollution residues affects mucociliary transport of urban public transport drivers and that administrative employees feel more pain than drivers. We hope to contribute with these results to preventive health policies according to the needs of this population / Introdução: A poluição atmosférica urbana vem sendo um dos maiores problemas que assolam a sociedade. No Pontal do Paranapanema existem vários fatores que contribuem para essa poluição, dentre eles ao aumento da frota de veículos registrado em Presidente Prudente, a falta de locais apropriados para destinação de resíduos sólidos e ainda a queima da palha da cana-de-açucar. Devido à grande área de contato entre a superfície do sistema respiratório e o meio ambiente, a qualidade do ar interfere diretamente na saúde respiratória. Assim podendo causar uma disfunção mucociliar que é responsável por episódios de exacerbações, o que ocasiona quadros de hipersecreção, infecções recorrentes e, consequentemente, dispneia. O sistema mucociliar é a primeira barreira mecânica a entrar em contato com esses poluentes atmosféricos e sua integridade é fundamental para a proteção do sistema respiratório. Atualmente os conceitos mais aceitos de qualidade de vida visam uma multiplicidade de dimensões. Objetivo: avaliar a influência dos resíduos da poluição atmosférica na saúde respiratória e qualidade de vida dos motoristas de transporte coletivo urbano em uma cidade do Pontal do Paranapanema. Metodologia: foram avaliados 30 indivíduos de ambos os sexos, que foram divididos em dois grupos: Grupo Controle – GC, constituído por 10 funcionários do setor administrativo e Grupo Motoristas – GM, constituído por 20 motoristas que ficam diretamente expostos à poluição. Foi realizada a mensuração de monóxido de carbono do ar expirado (COex), para a avaliação do transporte mucociliar nasal, foi utilizado o teste de tempo de trânsito de sacarina (TTS). Ambos realizados ao início e término da jornada de trabalho nos três momentos aferidos. A percepção da qualidade de vida (QV) foi analisada através da aplicação do questionário Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), aplicado antes do início da jornada de trabalho no primeiro dia de avaliação. Resultados: os resultados do teste TTS para o grupo motoristas apresentaram aumento da velocidade do transporte do primeiro para o terceiro dia de pesquisa. Já a percepção da QV foi observada que no domínio dor foi maior para os trabalhadores do Grupo Controle (p<0,05). Conclusão: exposição aos resíduos da poluição atmosférica afeta o transporte mucociliar de motoristas de transporte coletivo urbano e que os funcionários do setor administrativo, sentem mais dor do que os motoristas. Esperamos contribuir com esses resultados para as políticas preventivas de saúde de acordo com as necessidades dessa população.
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Pollution atmosphérique et reproduction humaine. / Atmospheric pollution and Human reproduction.Giorgis-Allemand, Lise 03 February 2017 (has links)
Une fraction importante de la population est exposée à la pollution atmosphérique ; ses effets sur la mortalité et la morbidité cardiovasculaire et respiratoire sont connus, et un effet de l'exposition au cours de la grossesse sur le poids de naissance et la croissance fœtale est probable ; un effet sur le risque de naissance prématurée a aussi été suggéré par de nombreuses études, essentiellement en Amérique. En revanche, la capacité des couples à concevoir -fertilité- et les paramètres de la fertilité féminine ont été très peu étudiés en lien avec cette exposition.L’objectif de ce doctorat était de documenter un effet éventuel de la pollution atmosphérique sur la fonction de reproduction humaine et tout particulièrement sur les caractéristiques du cycle menstruel, la probabilité de survenue d’une grossesse (fertilité) et le risque de naissance prématurée.Nous nous sommes appuyés sur une cohorte de couples n’utilisant pas de méthode contraceptive (l’Observatoire de la fertilité en France) et sur treize cohortes de naissances européennes participant au projet ESCAPE (European Study of Cohorts for Air Pollution Effects).Nous avons observé un allongement de la durée de la phase folliculaire du cycle menstruel (période du cycle entre le début des règles et l’ovulation) avec l’exposition de la femme aux particules en suspension dans l’atmosphère (n=158, β=1,6 jour pour une augmentation de la concentration des particules de diamètre aérodynamique inférieur à 10 µm -PM10- de 10 µg/m3 dans le mois précédant le cycle, intervalle de confiance, IC à 95%, 0,3; 2,9). En utilisant deux designs d’étude en parallèle sur la même population, l’approche des durées en cours et l’approche de cohorte prévalente, nous avons mis en évidence une tendance à une diminution de la probabilité de grossesse en association avec l’exposition à la pollution atmosphérique pour la première approche (cohorte prévalente : n=468, risque relatif de grossesse, HR : 0,69 pour une augmentation des PM10 de 10 µg/m3 dans les 70 jours précédant l’inclusion, IC à 95%, 0,43;1,12) ; la tendance était similaire avec l’approche des durées en cours (n=516, durée médiane sans contraception multipliée par 1,29 pour une augmentation des PM10 de 10 µg/m3 dans les 70 jours précédant l’arrêt de la contraception, IC à 95%, 0,97;1,70).Le risque de naissance prématurée, analysé avec un modèle de survie en prenant en compte l’exposition comme une variable dépendant du temps, n’était pas associé à divers polluants atmosphériques dans les cohortes du projet ESCAPE (n=46 791, OR=0,97 pour une augmentation du niveau moyen de PM10 de 10 µg/m3 pendant la grossesse, IC à 95%, 0,87 ;1,07). Nous avons par ailleurs mis en évidence une augmentation du risque de naissance prématurée avec la pression atmosphérique pendant le premier trimestre de grossesse et avec la température moyenne pendant le premier trimestre, au moins dans l’intervalle entre -5°C et 10°C. Nous avons montré qu’une partie de la littérature en faveur d’une association entre particules fines et risque de naissance prématurée pourrait être sujette à un biais causé par des durées de fenêtres d’exposition différentes entre les enfants nés avant terme et ceux nés à terme.Dans l’ensemble, ce travail confirme la nécessité d’utiliser un modèle de survie avec variables dépendant du temps pour étudier le risque de naissance prématurité et appelle à poursuivre les recherches concernant des effets possibles des polluants atmosphériques sur le cycle menstruel et la fertilité, pour lesquels nos travaux font partie des premiers réalisés en population générale. / A large fraction of the population is exposed to atmospheric pollution, which has known effects on cardiovascular and respiratory mortality and morbidity and probable effect on birthweight and fetal growth. So far, the biological aptitude to conceive for couples -fecundity- and the female markers of fecundity have been seldom studied in relation with this environmental exposure.The aim of this PhD was to quantify the possible association between atmospheric pollution and specific health outcomes related to human reproduction: menstrual cycle characteristics, probability of pregnancy and preterm birth risk. We relied on a population of couples not using any contraceptive method (Observatory of Fecundity in France) and on 13 birth cohorts participating in the European Study of Cohorts for Air Pollution Effects.We observed that higher levels of atmospheric pollutants during the 30 days before the start of a menstrual cycle were associated with longer follicular phase (n=158, β=1.6 days per each increase by 10 µg/m3 in particulate matters with an aerodynamical diameter of less than 10 µm -PM10; 95% confidence interval: 0.3;2.9). In the population recruited in OBSEFF study, we observed a trend for an increased time to pregnancy with short-term NO2 and PM10 levels in an original approach relying on two seldom used study designs focusing on a marker of fecundity in parallel: the prevalent cohort approach (n=468, hazard ratio of pregnancy, HR: 0.69 per each increase by 10 µg/m3 in PM10 during the 70 days before the inclusion, with a 95% CI of 0.43;1.12) and the current duration approach (n=516, median current duration of unprotected intercourse multiplied by 1.29 per each increase by 10 µg/m3 in PM10 during the 70 days before the contraception stop, 95% CI: 0.97;1.70). In the cohorts included in ESCAPE, preterm delivery risk studied by a survival model with time-dependent exposures was not associated with atmospheric pollutants levels during pregnancy (n=46,791, OR=0.97 per each increase by 10 µg/m3 in PM10 during the whole pregnancy, 95% CI 0.87;1.7). We observed an increased risk of preterm birth with higher atmospheric pressure during the first trimester of pregnancy and to some extent with temperature between -5°C and 10°C during the first trimester of pregnancy. We additionally showed that using exposure windows with different durations between cases and non-cases is a source of a bias in preterm birth studies that may impact several studies in the literature.This work demonstrated that using a survival model with time-dependent exposures is crucial to study preterm delivery risk. It appeals for additional research on the possible adverse effects of atmospheric pollution on menstrual cycle and fecundity, as our studies are among the first ones conducted in a general population on those topics.
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Biosurveillance des retombées atmosphériques à l'aide de bryophytes : suivi des hydrocarbures aromatiques polycycliques (HAP) à diverses échelles spatio-temporelles / Biomonitoring atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) with bryophytes at various spatial and temporal scalesFoan, Louise Marie 07 June 2012 (has links)
Les hydrocarbures aromatiques polycycliques (HAP) sont des polluants organiques persistants (POP) émis par les activités humaines suite à la combustion incomplète de la matière organique (industrie, chauffage, trafic routier...). En raison de leur faible taux de dégradation, de leur toxicité, de leur capacité à être transportés sur de longues distances et de leur bioaccumulation dans la matière organique, les HAP font l'objet d'une surveillance atmosphérique (directive cadre européenne 96/62/CE du 27 septembre 1996). Les bryophytes, plus communément appelées mousses, sont utilisées depuis une trentaine d'années pour la biosurveillance de la qualité de l'air. Leurs caractéristiques biologiques font de ces plantes terrestres d'excellents bioaccumulateurs des dépôts de polluants atmosphériques. Cependant, elles ont été peu utilisées pour la biosurveillance des HAP et pour des échelles spatiales et temporelles très limitées. Dans ce contexte, la thèse a pour objectif de valider l'utilisation de bryophytes comme outils pour la biosurveillance des retombées atmosphériques de HAP à différentes échelles spatio-temporelles. La première phase de ce travail a consisté en un développement analytique afin de valider l'analyse des HAP par chromatographie liquide associée à une détection par fluorescence (CLHP-FLD), l'extraction liquide-liquide des HAP contenus dans les dépôts totaux et l'extraction par liquide pressurisé (PLE) des HAP contenus dans les mousses. Cette dernière a été optimisée, grâce à la réalisation d'un plan d'expériences, et a été complétée par des tests de purification par extraction sur phase solide (SPE). Des études de terrain ont ensuite été réalisées afin d'évaluer les tendances temporelles à l'échelle saisonnière, annuelle et historique, ainsi que les tendances spatiales à l'échelle locale et régionale, des teneurs en HAP dans les mousses. Une étude menée sur des mousses d'herbier prélevées dans le Parc Naturel de Bertiz (Navarre, Espagne) entre 1879 et 2007 a permis d'identifier les sources historiques d'émission des HAP. Les bryophytes apparaissent comme de bons « témoins » de la contamination atmosphérique du passé. Une étude annuelle (2010-2011) de biosurveillance active menée à Bertiz a permis ensuite d'observer des tendances saisonnières des teneurs en HAP dans les mousses Hylocomium splendens (Hedw.) Schimp., liées aux variations des émissions atmosphériques et des conditions météorologiques, en particulier des précipitations. De plus, l'étude annuelle a révélé un fractionnement lors de l'accumulation par les mousses des HAP contenus dans les dépôts totaux, qui résulte d'une affinité des HAP pour les dépôts liée à leur solubilité et d'une affinité des HAP pour le végétal liée à leur propriété lipophile (KOW). Ainsi, le suivi des flux atmosphériques de HAP dans les dépôts totaux ne permet pas de prévoir a priori les teneurs de HAP dans les écosystèmes. Enfin, une analyse multivariée de la distribution spatiale des teneurs en HAP dans l'espèce Hypnum cupressiforme Hedw. prélevée en Espagne (Navarre), France (Île-de-France) et Suisse (Plateau Suisse et région de Bâle) a permis de caractériser les sources de contamination atmosphériques des régions étudiées et l'influence de paramètres environnementaux tels que l'altitude et la pluviométrie. / Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants (POPs) emitted by human activities during incomplete combustion of organic matter (industry, domestic heating, road traffic…). Due to their low degradation rates, toxicity, long-range transport and bioaccumulation in organic matter, PAHs are monitored in the atmosphere (Council Directive 96/62/EC of 27 September 1996). Bryophytes, more commonly called mosses, have been used during the past three decades for biomonitoring air quality. Because of their biological characteristics, these terrestrial plants are excellent bioaccumulators of airborne pollutants. However, few studies concern PAH biomonitoring and they are usually restricted to studies limited in time and space. In this context, the thesis aims to validate bryophytes as tools for biomonitoring atmospheric deposition of PAHs on various space-time scales. The first step of this work consisted in developing the analytical procedures in order to validate PAH analysis by liquid chromatography associated with fluorescence detection (HPLC-FLD), liquid-liquid extraction of PAHs from bulk deposition and pressurized liquid extraction (PLE) of PAHs from mosses. The latter was optimized with a factorial design and was completed by purification tests with solid phase extraction (SPE). Field studies were then carried out to evaluate temporal trends of PAH levels in mosses at seasonal, annual and historical scales, as well as spatial trends, at local and regional scales. A study undertaken on herbarium mosses sampled in Bertiz Natural Park (Navarra, Spain) between 1879 and 2007 leaded to the identification of PAH historical emission sources. Bryophytes appear as excellent “witnesses” of the past atmospheric contamination. An annual biomonitoring study (2010-2011) at Bertiz showed seasonal trends of PAH content in mosses Hylocomium splendens (Hedw.) Schimp., which are related to variations of PAH emissions and weather conditions, particularly precipitations. Moreover, the annual study revealed a fractionation of PAHs while they are transferred from total deposition to the mosses, as the affinity of PAHs for deposition samples was related with their solubility and their affinity for the plant was related to their lipophilic property (KOW). Thus, monitoring PAH fluxes in total deposition does not give an a priori estimation of PAH contents in the ecosystems. Finally, multivariate analysis of the spatial distribution of PAHs in the species Hypnum cupressiforme Hedw. sampled in Spain (Navarra), France (Île-de-France) and Switzerland (Swiss Plateau and Basel area) leaded to the characterization of the atmospheric contamination sources in the different areas and the influence of environmental parameters such as elevation and pluviometry.
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Stanovení míry znečištění atmosféry z družicových dat / Determination of atmospheric pollution from satellite dataHladká, Anna January 2013 (has links)
Determination of Atmospheric Pollution from Satellite Data Abstract The subject of this project is to determine air quality in Prague and the surrounding area based on satellite images and ground measurements data. The goal is to derive equations for calculating an amount of a specific pollutant over the entire area of the image. The first part of the thesis is devoted to the general theory and literature review related to this topic. The methodological part describes the steps of the procedure to handle the task, including e.g. converting satellite DN values to the radiometric values, atmospheric correction, regression analysis and mapping of the area of interest. Subsequently, the results are visualized, compared to the traditional interpolation methods and discussed. Finally, the contributions of this project and possible improvement of work on the topic are presented. Key words: Air pollution, Satellite images, Atmospheric correction, Regression analysis, Prague and surroundings
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Évolution de l'acidité et de la disponiblité en azote des sols forestiers français au cours du 20ème siècle : une approche spatio-temporelle et multi-échelle basée sur le caractère bio-indicateur de la flore / Evolution of the acidity and nitrogen availability in French forest soils over the 20th century : a spatiotemporal and multiscale approach based on the bioindicator character of plantsRiofrio Dillon, Gabriela 28 June 2013 (has links)
Les activités humaines ont, depuis plus d'une centaine d'années, influencé de plus en plus fortement les cycles géochimiques contrôlant les niveaux d'acidité et de disponibilité en azote dans la nature. Les dépôts acides et azotés conduisent à une modification des conditions du milieu et notamment à des changements sensibles de la composition des communautés d'espèces végétales. L'objectif de cette thèse est de retracer l'évolution spatio-temporelle de l'acidité et de la disponibilité en azote des sols forestiers français au cours du 20ème siècle à partir du caractère bio-indicateur de la flore, à l'échelle locale ainsi globale. L'utilisation de la flore comme bio-indicateur vise à pallier l'absence de données de mesures directes des conditions édaphiques et des dépôts atmosphériques acides et azotés couvrant une large emprise spatio-temporelle. Premièrement, les variations de pH (indicateur d'acidité) et C:N (indicateur de disponibilité en azote) bio-indiquées ont été calculées à partir d'environ 100 000 relevés floristiques temporaires réalisés dans toute la France de 1910 à 2010. Elles ont été analysées par une méthode novatrice de comparaison spatio-temporelle, en différenciant les zones forestières sur substrat acide et non-acide ainsi que les forêts de conifères et de feuillus. Dans un second temps, nous avons analysé les changements des conditions édaphiques entre 1972 et 2011 à l'échelle de la forêt de Villey-Le-Sec, et ceux de la flore qu'ils induisent en lien avec d'autres évolutions environnementales, toujours à partir du caractère bio-indicateur de la flore.À l'échelle globale, nous avons observé une acidification des forêts françaises en milieu acide (-0.34 unités du pH en moyenne) et milieu non-acide (-0.19 unités du pH en moyenne), respectivement, jusqu'en 1984 et 1997. Nous avons ensuite mis en évidence, pour la première fois à notre connaissance, un arrêt dans l'acidification des sols forestiers et même une diminution de l'acidité sur substrat non-acide ainsi que un décalage temporel entre l'acidification des zones acides et non-acides. Cette évolution apparaît tout à fait cohérente avec celle connue des dépôts atmosphériques acidifiants en France depuis le début du 20ème siècle. Spatialement, nous confirmons la tendance temporelle, montrons une évolution régionalisée de l'acidification principalement sur substrat non-acide et soulignons la grande variabilité spatiale des changements de pH des sols forestiers. Concernant l'évolution de la disponibilité en azote, nous observons une diminution non attendue de celle-ci jusqu'en 1984 et 1997, respectivement, dans les forêts de conifères (+0.79 unités de C:N en moyenne) et de feuillus (+0.74 unités de C:N en moyenne). Une tendance à l'eutrophisation des sols forestiers a ensuite été observée dans les forêts de conifères et de feuillus à partir de 1997 (-0.10 et -0.16 unités de C:N en moyenne, respectivement). Cette évolution apparaît décalée par rapport à celle des dépôts azotés en France. [...] Suite et fin du résumé dans la thèse. / Human activities have, over the last century, strongly influenced the cycles controlling the levels of acidity and nitrogen availability in nature. Acidifying and eutrophying deposition lead to a change in environmental conditions and particularly to sensitive changes in plant communities' composition.The objective of this Ph.D work is to reconstruct the spatiotemporal evolution of the acidity and nitrogen availability in French forest soils over the 20th century using the bioindicator character of plants, into local and global scales. The use of plants as bioindicator seeks to mitigate the lack of direct measurements of soil conditions and atmospheric deposition, over a wide spatiotemporal extent. First, changes in bioindicated soil pH (indicator of acidity conditions) and C:N (indicator of nitrogen availability status) were computed from approximately 100 000 temporary floristic plots carried out throughout France from 1910 to 2010. They were analyzed using an innovative method of spatiotemporal comparison, where acidic and nonacidic forest areas and coniferous and broadleaved forests were differentiated. Secondly, and always from the bioindicator character of plants, changes in soil conditions between 1972 and 2011 across Villey forest as well as floristic changes they induce related with other environmental changes were analyzed.At the global level, we observed acidification in acidic forest areas (-0.34 pH units on average) and in nonacidic areas (-0.19 pH units on average), respectively, until 1984 and 1997. We demonstrated for the first time (to our knowledge) a cessation of acidification of forest soils and even a decrease in acidity in nonacidic forest areas, as wella as a time lag for acidification between acidic and nonacidic areas. This trend is consistent with the trend of acidifying deposition in France since the early 20th century. Spatially, our results confirm the temporal trends, show a regional geographic pattern of acidification (mainly observed in nonacidic areas), and highlight the high spatial variability of soil pH changes. Concerning the evolution of nitrogen availability conditions, we observed an unexpected decrease in available nitrogen until 1984 and 1997, respectively, in coniferous (+0.79 C:N units on average) and broadleaved forests (+0.74 C:N units on average). A trend to eutrophisation of forest soils was then observed in coniferous and broadleaved forests since 1997 (-0.10 and -0.16 C:N units on average, respectively). This trend is not consistent with the trend of nitrogen atmospheric deposition in France. ”Last and final summary in the thesis.”
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Advanced modelling of porous screens in aerodynamic diffusers using variable resistance factorsJanse van Rensburg, Jacobus Johannes 12 1900 (has links)
Thesis (M. Tech. Mechanical engineering -- Vaal University of Technology / Strict emission legislation has forced industry in general to seriously consider the
negative impact it has on the environment, specifically concerning emissions from
burning fossil fuel into the atmosphere. In cases where emission levels exceed the
allowable limit, companies are forced to operate at lower operating conditions and
these load losses can result in a significant loss of revenue. This has forced
companies to improve their ash filtering capabilities by optimising electrostatic
precipitation systems.
One of the main factors impacting on the efficiency of such a system is the distribution
of the flow across the collection plates. The design of the inlet diffuser plays a major
role in the ultimate distribution of the flow through the precipitator. Porous screens are
positioned in the diffuser in order to distribute the flow across the total flow area with
the aim to achieve a uniform distribution of the flow.
CFD is widely used in industry to simulate the flow through precipitators in order to
optimise the flow distribution and thus increase the efficiency of the system. It was
found however that the current methods used to simulate these screens in CFD models
were not well researched and employed fixed resistance values that could not reliably
compensate for changes in the resistance coefficient due to a change in the angle of
incidence.
This study investigates advanced numerical methods for the simulation of porous
screens in applications where the angle of incidence changes continuously across the
face of the screen. New methods are introduced where the resistance of the screen is
calculated as a function of the changing angle of incidence. The methods currently
used are also investigated and compared with results from the new methods.
Extensive experimental work was required to supply empirical data for the validation of
the numerical methods that are proposed. For this reason, the first part of this study
focused on the design construction and commissioning of a low speed wind tunnel.
Results are presented and discussed for flow profiles through wide-angle diffusers at
different angles and also for a number of different screens positioned in the centre of
the diffuser.
This study also investigates the sensitivity of a CFD simulation code to factors such as
numerical discretisation schemes, turbulence models and solution relaxation
specifically for wide-angle diffusers. These factors were tested for diffusers at different
angles and included tests on open diffusers and also with screens positioned inside the
diffuser.
It was concluded that the current methods used are not adequate to capture the true
flow profiles for a range of different screen geometries. Although the proposed models
did improve on the limitations of the current methods, it was found that the applicability
of these models is still limited and that further research would be required to develop
numerical methods that are valid for a wide range of applications. / Vaal University of Technology, The National Research Foundation (NRF) and Eskom TSI
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Anéis de crescimento do lenho de árvores como monitores ambientais: avaliação temporal e espacial da poluição atmosférica na cidade de Paulínia, São Paulo / Tree rings as environmental monitors: temporal and spatial assessment of air pollution in Paulínia city, São PauloChagas, Matheus Peres 20 May 2013 (has links)
O presente estudo tem por objetivo aplicar a análise dos anéis de crescimento de espécies arbóreas no monitoramento ambiental de uma área urbana com histórico de poluição atmosférica. Foram selecionadas árvores das espécies Caesalpinia pluviosa var. peltophoroides (Fabaceae-Caesalpinaceae) e Tabebuia pentaphylla (Bignoniaceae) e, do seu tronco, foram extraídas amostras do lenho através do método não destrutivo. A área de estudo selecionada foi o Distrito Industrial de Betel, município de Paulínia/SP, Brasil, cujo histórico de poluição ambiental de origem antropogênica é fornecido pela Companhia de Tecnologia de Saneamento Ambiental (CETESB) e através de estudos recentes encontrados na literatura especializada. Ainda, foram selecionas três outras áreas, nos municípios de Paulínia e Piracicaba, distantes em 10, 15 e 60 km, estabelecendo-se um gradiente ambiental de pressão antrópica. Foram aplicadas as análises: (i) caracterização anatômica macro e microscópica e densitometria de raios X, na identificação dos anéis de crescimento do lenho, (ii) dendrocronológica, na datação e avaliação do crescimento radial das árvores, (iii) climática, no estudo da influência dos fatores climáticos no crescimento anual das árvores e (iv) química, na determinação da composição de macro e micronutrientes e de elementos potencialmente tóxicos nos anéis de crescimento do lenho, através da aplicação das técnicas analíticas espectrometria de emissão óptica com plasma induzido por laser (LIBS) e espectrometria de emissão óptica por plasma acoplado indutivamente (ICP OES). Os resultados indicaram que, para as duas espécies, os anéis de crescimento possuem características anatômicas marcantes, correlacionadas com os valores de densidade aparente, que possibilitam a determinação da idade das árvores. A análise das séries temporais de largura de anéis de crescimento demonstrou que as árvores apresentam crescimento sincrônico, condicionado as condições específicas do ambiente onde estão crescendo. A constatação da ausência de um sinal climático comum determinando o crescimento das árvores nos 3 sítios sugere a influência de outros fatores, entre eles, a proximidade em que as árvores se encontram em relação às fontes estacionárias de poluição atmosférica, verificada através dos valores de incremento radial obtidos, sempre menores para as árvores localizadas no Distrito de Betel. A análise da composição química dos anéis de crescimento (ICP OES) revelou diferenças na absorção de elementos químicos entre as árvores das duas espécies e também entre as árvores da mesma espécie crescendo em diferentes locais. Ainda, a avaliação dos valores de intensidade das linhas de emissão dos analitos identificou padrões temporais de fixação de elementos químicos no lenho, com tendência comum para alguns, nos sítios de menor influência antrópica. Também, evidenciou os períodos de maior fixação de elementos com potencial tóxico no troco das árvores (ex. Al, B, Cu, Fe e Na), relacionados com os anos do início das atividades indústrias no Distrito de Betel. Os resultados obtidos neste estudo permitiram concluir que a análise dos anéis de crescimento das árvores de C. pluviosa e T. pentaphylla possui grande potencial no monitoramento ambiental. / This study aims to apply tree rings analysis on environmental monitoring of an urban area with air pollution history. Caesalpinia pluviosa var. peltophoroides (Fabaceae- Caesalpinaceae) and Tabebuia pentaphylla (Bignoniaceae) trees were selected and wood samples were extracted from their trunk by a non-destructive method. The study area was the Industrial District of Bethel, Paulínia, São Paulo State, Brazil. Its environmental pollution history of anthropogenic origin is provided by the Company of Environmental Sanitation Technology (CETESB) and by recent studies of specialized literature. Three other areas in the municipalities of Paulínia and Piracicaba were also selected, establishing an environmental gradient of anthropogenic pressure within 10, 15 and 60 km distance. The following analyses were applied: (i) macro and microscopic anatomical characterization and X-ray densitometry, for tree rings limits identification (ii) dendrochronological, in dating and evaluating of radial growth, (iii) climatic, analyzing the climatic factors influence on annual growth and (iv) chemical, determining the composition of macro and micronutrients and potentially toxic elements in the tree rings through the application of the analytical techniques Laser Induced Breakdown Spectroscopy (LIBS) and inductively coupled plasma optical emission spectrometry (ICP OES). The results indicated that tree rings formed in both species have remarkable anatomical features correlated with apparent density values, enabling the determination of tree age. The analysis of tree rings\' width time series showed that trees exhibit synchronous growth, conditioned by the specificities of the environment where they are growing. The verification of an absent common climate signal determining the tree growth among the 3 studied sites suggests the influence of other factors, including the proximity of trees in relation to stationary sources of air pollution, verified through the obtained values of radial increment, always lower for trees located in the District of Bethel. The tree rings chemical composition analysis (ICP OES) revealed differences in the absorption of chemical elements among trees species and among individuals of the same species growing in different locations. The emission lines intensities assessment (LIBS) analysis identified temporal patterns of chemical elements fixation in wood, with a common trend for those located at sites with lower anthropogenic influence. It also showed periods of increased fixation of potentially toxic elements in tree trunk (e.g Al, B, Cu, Fe, and Na), related to the early years of industrial activities in the District of Bethel. The results obtained in this study allowed us to conclude that the tree rings analysis of C. pluviosa and T. pentaphylla has great potential for environmental monitoring.
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