Le formaldéhyde, un des produits de base de la chimie, est synthétisé industriellement par un procédé multi-étapes, dans lequel l’efficacité énergétique est limitée. Ainsi, une synthèse par oxydation directe du méthane en phase gazeuse, qui pourrait être plus avantageuse, a été étudiée expérimentalement et par une modélisation cinétique, dans le cadre de ce travail. Pour favoriser la production du formaldéhyde, produit intermédiaire de l’oxydation du méthane, des temps de passage faibles (< 100 ms) ont été envisagés. Un microréacteur annulaire (espace annulaire de 0,5 mm) en quartz a été utilisé, dans lequel la réaction a été étudiée en faisant varier les paramètres opératoires suivants : température (600-1000°C), temps de passage (20-80 ms), rapport XO2/XCH4 (0,5-15) et teneur en NO2 ajoutée (0-0,6%). Sans NO2, les sélectivités en HCHO diminuent avec la conversion et le rendement maximal sans recyclage est de 2.4% (950°C, 60 ms et XO2/XCH4 = 8). L’ajout de NO2 permet de diminuer la température requise de 300°C, et d’augmenter le meilleur rendement en HCHO à 9% (700°C, 30 ms et XO2/XCH4 = 7 et 0,5% de NO2). À faible avancement, la réaction sans NO2 peut être modélisée avec le mécanisme Gri-Mech 3.0 sans aucun ajustement. Pour la réaction avec NO2, après quelques corrections et modifications fondées sur une étude bibliographique, le mécanisme de Zalc et al. (2006) permet de rendre correctement compte des résultats expérimentaux. L’analyse de flux a montré que l’inter-conversion entre NO2 et NO joue un rôle important dans le milieu réactionnel. Elle permet de former continuellement les radicaux réactifs OH•, et de convertir les radicaux CH3• et CH3O2• en radicaux CH3O• / Formaldehyde is one of the world’s top organic intermediate chemicals. It is currently produced by a complex three-step process but a one-step process might require less energy. In this work, the direct gas phase partial oxidation of methane to formaldehyde has been studied through experiments and kinetic modeling. As formaldehyde is an intermediate in the sequential oxidation of methane, short residence times (<100 ms) have been considered in order to optimize its production. Thus, a quartz annular flow microreactor (annular space 0.5 mm wide), was chosen. The undertaken experiments consist of a systematic investigation of the effects of temperature (600-1000°C), residence time (20-80 ms), input composition XO2/XCH4 (0.5-15) and initial NO2 concentration (0-0.6%). Without NO2, the HCHO selectivity decreases with the increasing methane conversion. For a single pass operation, the best HCHO yield is 2.4% (950°C, 60 ms, XO2/XCH4 = 8). The addition of NO2 decreases the reaction initiation temperature by 300°C and it remarkably enhances the HCHO yield. The highest HCHO yield attains 9% (700°C, 30 ms, XO2/XCH4 =7) in the presence of NO2 (0.5%). For the reaction without NO2, the mechanism Gri-Mech 3.0 fits well the experimental results. For the reaction with NO2, by using the mechanism of Zalc et al. (2006) with some modifications, we obtained a good agreement between the experimental data and the model. The production and consumption flux analysis shows that the inter-conversion between NO2 and NO plays an important role in the reaction, because it continuously produces the reactive radicals OH• and it converts the radicals CH3• and CH3O2• to radicals CH3O•

Tese (doutorado)—Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Ecologia, Programa de Pós-Graduação em Ecologia, 2008. / Submitted by Jaqueline Oliveira (jaqueoliveiram@gmail.com) on 2008-11-20T17:19:01Z No. of bitstreams: 1 TESE_2008_ErikaBFernandes.pdf: 899635 bytes, checksum: 08b5a7a9b5269f642cdaede41e9ba7e8 (MD5) / Approved for entry into archive by Georgia Fernandes(georgia@bce.unb.br) on 2009-02-04T16:30:59Z (GMT) No. of bitstreams: 1 TESE_2008_ErikaBFernandes.pdf: 899635 bytes, checksum: 08b5a7a9b5269f642cdaede41e9ba7e8 (MD5) / Made available in DSpace on 2009-02-04T16:30:59Z (GMT). No. of bitstreams: 1 TESE_2008_ErikaBFernandes.pdf: 899635 bytes, checksum: 08b5a7a9b5269f642cdaede41e9ba7e8 (MD5) / O objetivo desse estudo foi avaliar as emissões de CO2, NO e N2O em Latossolos sob diferentes sistemas de cultivo em plantio direto na região do Cerrado. Os resultados são apresentados em três capítulos. O Capítulo 1 refere-se ao estudo dos efeitos de doses crescentes de fertilizante nitrogenado nos fluxos de gases traço ao longo do ciclo de cultivo de milho de sequeiro (nov.2004 a abr.2005). O experimento foi desenvolvido na Fazenda Dois J1 (município de Rio Verde, Goiás) em blocos ao acaso, com três repetições para testar dois níveis de nitrogênio (70 e 120 kg N ha-1) contra tratamento controle (sem adição de N) e dois locais de coleta (linha e entrelinha de plantio). A adição de 20 kg de N ha-1 na linha de plantio na forma de uréia um dia após o plantio não foi suficiente para alterar os valores de fluxo de N-NO. Vinte e oito dias após a emergência, a adição de 50 kg de N ha-1 em cobertura na forma de uréia (tratamento N1), incrementou os fluxos de N-NO na linha (12,5 ± 9,4 ng N-NO cm-2 h-1) e entrelinha (3,2 ± 1,7 ng N-NO cm-2 h-1) em relação ao controle (0,5 ± 0,2 ng N-NO cm-2 h-1) e a adição de 100 kg de N ha-1 em cobertura na forma de uréia (tratamento N2) incrementou os fluxos de N-NO na linha (7,7 ± 4,3 ng N-NO cm-2 h-1) e entrelinha (4,4 ± 2,1 ng N-NO cm-2 h-1) em relação ao controle (0,4 ± 0,3 ng N-NO cm-2 h-1). Os fluxos de N-N2O na linha aumentaram após a aplicação dos tratamentos N1 e N2 e variaram de 0,9 a 4,4 ng N-NO cm-2 h-1, enquanto o valor médio no tratamento controle foi –1,7 ng N-NO cm-2 h-1. Não houve diferença significativa para os fluxos de óxidos de N entre os dois níveis de N e entre linhas e entrelinhas. A disponibilidade de N-NH4 + explicou os fluxos de N-NO nos tratamentos N1 e N2, linha e entrelinha. Os fluxos de C-CO2 não foram alterados com as fertilizações aplicadas e responderam positivamente à disponibilidade de água no solo. O Capítulo 2 aborda três sistemas de produção em plantios comerciais: 1. Rotação milho-Brachiaria-feijão irrigado (ago.2003 a fev.2004), 2. Soja em monocultivo de verão seguida de vegetação espontânea (nov.2003 a abr.2004), 3. Algodão não irrigado em monocultivo de verão cultivado sob palhada de Brachiaria (nov.2004 a ago.2005). Os estabelecimentos rurais avaliados estão situados no município de Cristalina, Goiás (Fazenda Dom Bosco para os sistemas 1 e 2, e Fazenda Pamplona para o sistema 3). Em cada sistema de cultivo foi estabelecida uma parcela (10 x 15 m) onde se procedeu à determinação dos fluxos de NO, N2O e CO2, temperatura do solo, N mineral disponível, biomassa microbiana e espaço de poros preenchido por água, ao longo do ciclo das culturas avaliadas. Adicionalmente, foram abertas três trincheiras para determinação dos estoques de C e N do solo até 30 cm de profundidade. Nos cultivos de verão, a entrada de nitrogênio via fertilização elevou predominantemente os fluxos de N-NO em comparação a N-N2O. No milho a adição de 103,2 kg N ha-1 elevou os fluxos para 3,9 ng N-NO cm-2 h-1 e a adição de 18,4 kg N ha-1 elevou para 8,8 ng N-NO cm-2 h-1, no algodão a adição de 90 kg N ha-1 elevou os fluxos para 39,3 ± 20,1 ng N-NO cm-2 h-1 (linha) e para 83,3 ± 11,9 ng N-NO cm-2 h-1 (entrelinha). No cultivo da soja os fluxos de N-NO foram semelhantes aos da área de cerrado nativo utilizada para comparação. No feijão irrigado, cultivado no inverno, a N-fertilização elevou tanto os fluxos de N-NO quanto os de N-N2O, após a adição de 81,0 kg N ha-1 o fluxo de N-NO foi 5,0 ng N-NO cm-2 h-1 e o de N-N2O foi 2,3 ng N-N2O cm-2 h-1, e após a adição de 2,4 kg N ha-1 o fluxo de N-NO foi 12,2 ng N-NO cm-2 h-1 e o de N-N2O foi 10,6 ng N-N2O cm-2 h-1. Fluxos de N-N2O elevados foram medidos durante a senescência das plantas de feijão irrigado (1,7 ± 1,2 ng N-N2O cm-2 h-1), soja (3,8 ± 1,2 ng N-N2O cm-2 h-1) e algodão (1,6 ± 2,7 ng N-N2O cm-2 h-1). Os Fatores de Emissão de N-NO Induzida por fertilizantes foram 0,1% (milho), 0,2% (feijão irrigado) e 0,4% (algodão). Para o N-N2O foram, 0,3% (milho), 0,2% (feijão irrigado) e 0,2% (algodão). Em relação à área nativa, a respiração do solo foi maior no cultivo do feijão irrigado (0,8 a 1,8 mmol C-CO2 m-2 s-1), menor no cultivo do algodão (0,2 a 2,3 mmol C-CO2 m-2 s- 1) e semelhante nos cultivos de soja e milho (0,5 a 1,8 mmol C-CO2 m-2 s-1). O Capítulo 3 aborda o sistema de Integração Lavoura-Pecuária-ILP (nov.2003 a abr.2005), também na Fazenda Dom Bosco (município de Cristalina, Goiás). A ILP caracterizou-se pelo cultivo do feijão de sequeiro sobre palhada de Panicum (dez.2003 a mar.2004), seguido de sorgo para silagem em consórcio com Panicum (mar. a jun.2004), pousio (jul. a nov.2004) e pastagem de Panicum regenerada (nov.2004 a abr.2005). Em comparação com o cerrado nativo, fluxos de N-NO mais altos foram registrados após o plantio (8,9 ng N-NO cm-2 h-1) e na senescência do feijão (5,7 ng N-NO cm-2 h-1), após a fertilização do sorgo (8,6 ng N-NO cm-2 h-1) e no crescimento da pastagem (8,2 ± 7,1 N-NO ng cm-2 h-1) que também apresentou fluxos de N-N2O altos (14,1 ng N-N2O cm-2 h-1). Fluxos altos de C-CO2 foram mensurados após a fertilização do sorgo (1,6 mmol C-CO2 m-2 s-1) e durante o cultivo da pastagem (2,8 mmol C-CO2 m-2). Estimou-se uma perda de 0,6 Mg C ha-1 ano-1 e de 0,3 Mg C ha-1 ano-1 nos estoque de C do solo (0 a 30 cm) na área da soja em 31 anos sob cultivo e da rotação milho-feijão irrigado em 10 anos, respectivamente. Após 8 anos de implantação do sistema ILP, em uma área que esteve anteriormente sob cultivo convencional de soja (10 anos) e pastagem (13 anos) e, no algodão cultivado sob a palhada de Brachiaria após 27 anos não foram detectadas diferenças nos estoques de C e N do solo em relação à área de cerrado nativo. Os resultados indicam que sistemas de cultivo diversificados, a exemplo da ILP, favorecem a manutenção de C e N no solo. Tais sistemas colocam-se como uma alternativa para a recuperação de solos agrícolas degradados e para a sustentabilidade ambiental em áreas agrícolas já estabelecidas. No entanto, é necessária a adoção de práticas que melhorem a eficiência da fertilização nitrogenada e do uso de N pelas diferentes culturas, reduzindo as perdas de N na forma de NO e N2O. Embora os Fatores de Emissão de N2O e de NO Induzida por fertilizantes calculados nesse estudo sejam inferiores aos estabelecidos pelo IPCC, há um aumento das emissões em áreas cultivadas em relação às áreas sob vegetação nativa de Cerrado que pode ser significativo quando se considera a extensão territorial voltada para produção agrícola no Cerrado. _______________________________________________________________________________ ABSTRACT / The objective of the study was to evaluate the CO2, NO, N2O emissions from Oxisols (Latossolos) under different no-till cropping systems in the Cerrado region (Central Brazil). The results are presented in three chapters. Chapter 1 presents a study on the effects of increasing doses of nitrogen fertilizer on the fluxes of trace gases along the crop cycle of non-irrigated maize (Nov.2004 to Apr.2005). The experiment was carried out in the municipality of Rio Verde (Federal State of Goiás) (DoisJ1 Farm) in randomized blocks with three repetitions. Two levels of nitrogen were tested (70 and 120 kg N ha-1) comparing rows and between rows. Control treatment consisted of no addition of N fertilizer. The broadcasting fertilization with 50 kg N ha-1 (as urea) (treatment N1) increased the NO-N fluxes in the rows (12.5 ± 9.4 ng NO-N cm-2 h-1) and between the rows (3.2 ± 1.7 ng NO-N cm-2 h-1) compared to control treatment (0.5 ± 0.2 ng NO-N cm-2 h-1). The broadcasting fertilization with 100 kg N ha-1 (as urea) (treatment N2) increased the NO-N fluxes in the rows (7.7 ± 4.3 ng NO-N cm-2 h-1) and between the rows (4.4 ± 2.1 ng NO-N cm-2 h-1) compared to control treatment (0.4 ± 0.3 ng NO-N cm-2 h-1). N2O-N fluxes in the rows were increased after the N1 and N2 application and ranged from 0.9 to 4.4 ng NO-N cm-2 h-1 against -1.7 ng NO-N cm-2 h-1. in the control treatment. N oxides fluxes did not differ significantly between N1 and N2, and rows and between the rows. Availability of NH4 +-N explained NO-N fluxes in N1 and N2 treatment, in the rows and between the rows. Fluxes of CO2–C fluxes were not influenced by N fertilization but responded positively to increasing soil humidity. Chapter 2 presents a study comparing three cropping systems in commercial plantations: 1. maize-Brachiaria-irrigated bean rotation (Aug.2003 to Feb.2004), 2. soybean monoculture followed by natural fallow (Apr.2004 to Nov.2003), 3. Non irrigated cotton after Brachiaria ruzizienses (Aug.2005 to Nov.2004). The commercial plantations are located in the municipality of Cristalina (Federal State of Goiás, Brazil) (Dom Bosco Farm for systems 1 and 2, and Pamplona Farm for the system 3). One plot (10 x 15 m) was established in each cropping system for measurements of NO-N, N2O-N and CO2-C fluxes, air and soil temperature, inorganic-N availability, microbial biomass and soil water-filled pore space along crop cultivation periods. Additionally, three soil trenches from 0-30 cm depth were opened to determine the C and N soil stocks. In the summer crops, the fertilization with N induced predominantly NO-N fluxes compared to N2O-N fluxes. During maize cultivation, the addition of 103.2 kg N ha-1 increased NO-N fluxes to 3.9 ng NO-N cm-2 h-1 and the addition of 18.4 kg N ha-1 to 8.8 ng NO-N cm-2 h-1. During cotton cultivation, the addition of 90 kg N ha-1 increased NO-N fluxes to 39.3 ± 20.1 ng NO-N cm-2 h-1 (in the rows) and to 83.3 ± 11.9 ng NO-N cm-2 h-1 (between the rows). During soybean cultivation, NO-N fluxes were similar to those from native cerrado area used for comparison. During cultivation of bean with irrigation (winter), N-fertilization increased both NO-N and N2O-N. After addition of 81.0 kg N ha-1, NON flux was 5.0 ng NO-N cm-2 h-1 and N2O-N was 2.3 ng N2O-N cm-2 h-1 and after the subsequent addition of 2.4 kg N ha-1 fluxes were even higher (NO-N = 12.2 ng NO-N cm-2 h-1 and N2O-N = 10.6 ng N2O-N cm-2 h-1). High N2O-N fluxes were measured during the senescence of irrigated bean (1.7 ± 1.2 ng N2O-N cm-2 h-1), soybean (3.8 ± 1.2 ng N2O-N cm-2 h-1) and cotton (1.6 ± 2.7 ng N2O-N cm-2 h-1). Fertilizer-induced emission factors (FEI) estimated in this study for NO-N were 0.1% (maize), 0.2% (irrigated beans) and 0.4% (cotton) while for N2O-N were 0.3% (maize), 0.2% (irrigated beans) and 0.2% (cotton). Comparing with an area under native cerrado vegetation, soil respiration was higher under cultivation of bean with irrigation (0.8 to 1.8 mmol CO2–C m-2 s-1), lower under cotton cultivation (0.2 to 2.3 mmol CO2–C m-2 s- 1) and similar under soybean and maize cultivation (0.5 to 1.8 mmol CO2–C m-2 s-1). Chapter 3 presents results regarding the pasture-crop integrated system (Nov.2003 to Apr.2005), located in the municipality of Cristalina, Goiás (Dom Bosco Farm). The pasture-crop integrated system is a sequence of the non irrigated bean cultivated under Panicum straw (Dez.2003 to mar.2004), sorghum-Panicum intercropping (Mar.2004 to Jun.2004), uncovered soil (Jul.2004 to Nov.2004) and pasture (Nov.2004 to Abr.2005). Comparing with an area under native cerrado vegetation, higher NO-N fluxes were measured after planting (8.9 ng NO-N cm-2 h-1), during the senescence of bean (5.7 ng NO-N cm-2 h-1), after sorghum fertilization (8.6 ng NO-N cm-2 h-1) and under growing Brachiaria (8.2 ± 7.1 NO-N ng cm-2 h-1). During Brachiaria cultivation higher N2O-N fluxes (14.1 ng N2O-N cm-2 h-1) were also measured. Higher CO2-C fluxes were measured after sorghum fertilization (1.6 mmol CO2–C m-2 s-1) and again during Brachiaria cultivation (2,8 mmol CO2–C m-2). Estimated losses of C stocks were 0.6 Mg C ha-1 yr-1 after 31 years under soybean monoculture followed by natural fallow and 0.3 Mg C ha-1 yr-1 after 10 years under maize-Brachiaria-irrigated bean rotation. There no differences in soil C and N stocks between the area under native cerrado vegetation and after 27 years of cotton cultivated under Brachiaria straw and after 8 of pasture-crop integrated that was implemented after soybean under conventional system (10 years) and pasture (13 years). Rotation systems, as pasture-crop integrated system, are good options to recover degraded agricultural soils and to improved environmental sustainability in agricultural areas already established. However, there is a need to adopt practices that improve the efficiency of nitrogen fertilization and use of N by different crops to reduce N losses via NO and N2O emissions to the atmosphere. Although FEI from NO and N2O estimated in this study are lower than those established by the IPCC, emissions from cultivated areas compared to areas under native Cerrado vegetation can be of relevance when territorial extension dedicated to agricultural production in Cerrado is considered.

The aim of the thesis was to prove the efficiency of aquatic plants in removing of water biogens, to produce a list of aquatic plants suitable for this purpose and laboratory verification of the selected plants which were monitored for pH, conductivity, total N, total P, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, plant growth capes and light intensity. Data obtained in experiments by laboratory measurements are processed into a graphic form and there are also available tables of measured values. Experiments were carried out in the classroom and anjanced laboratory building of the M Mendel University in the period from 17.6.2015 to 31.3. 2016. The selected plants for tests became duckweed (Lemna minor) and reed canary grass (Phalaris arundinacea). Tests were carried out in the length of 7 to 14 days for the duckweed and 7.5 months for the canary. Measured results confirmed the information obtained from other works and verified the results.

An emission inventory tool for estimating SO2, NO2, and PM10 emissions from brick clamp kiln sites was developed from investigations performed on three representative South African clamp kiln sites in order to facilitate application for Atmospheric Emission Licenses (AELs) from these sources. The tool utilizes readily available site-specific parameters to generate emission factors for significant activities that emit the aforementioned pollutants. PM10 emission factors for significant processes were developed using empirical expressions from the Compilation of Air Pollutant Emission Factors (AP-42) documents. SO2 emission factor for clamp kiln firing was obtained from “reverse-modelling”, a technique that integrates ambient monitoring and dispersion modelling (using Atmospheric Dispersion Modelling System software) to “standardize” actual emission rate from an assumed rate of 1 g/s. The use of multiple point sources proved to improve the simulation of the buoyancy-induced plume rise; therefore, a “bi-point” source configuration was adopted for the kiln. The “reverse-modelling” technique and “bi-point” source configuration produced SO2 emission rates differing from -9 % to +22 % from mass balance results, indicating that the “reverse-modelling” calculations provide reliable emission estimates for SO2. An NO2 emission factor could not be obtained from the “reverse-modelling” technique due to experimental errors and the significant effect of NO2 emissions from other onsite air emission sources such as internal combustion engines. The NO2 emission factor was obtained from previous comprehensive study on a similar clamp kiln site. The emission factors obtained from this study were utilized in developing an “emission inventory tool” which is utilized by clay brick manufacturers in quantifying air emissions from their sites. Emissions quantification is a requirement for brick manufacturers to obtain an AEL which is regulated under South African environmental laws. It is suggested that the technique used here for SO2 emission confirmation could be used to estimate emissions from a volume or area source where combustion occurs and where knowledge of the source parameters is limited. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Chemical Engineering / unrestricted

Air pollution is a global problem and concern that affects every nation around the world.One of the chemical elements that is part of bad air quality is Nitrogen Dioxide (NO2).Children are a vulnerable group to air pollution due to their immature health system, thusplanning for safe and healthy neighborhoods is essential for their future development.Sweden is a one of the international leaders of sustainable development, with Gothenburgone of the main cities in the country that has an impressive ecological concern. The purposeof this study is to measure the exposure of children, ages 0 – 15 years old, to NO2 on aneighborhood level in Gothenburg.With the use of the software ArcGIS 10.6.1 and the spreadsheet Microsoft Excel, it waspossible to analyze the neighborhoods where children live and are exposed to bad air qualityas well as identify family neighborhoods that might also be high pollution areas. The resultsshow different conclusions between the age groups of children while the mean levels of airpollution are mostly concentrated in the city center.

La contaminació atmosfèrica és un problema de salut pública, causa més de 380 000 morts a la Unió Europea. La present tesis té per objectius avaluar l'exposició i efectes sobre el tracte respiratori de la contaminació provinent del tràfic. Les concentracions exteriors y personals de sulfurs i de carbó són bons indicadors de exposició personal en una ciutat mediterrània; per a PM2.5 hi ha altres fonts a considerar. La molèstia deguda a la contaminació no és un bon indicador d'exposició, però reflecteix la percepció del subjecte. La contaminació que prové del tràfic augmenta els símptomes d'asma y probablement també causa asma en adults. El PM2.5 provinent de la combustió augmenta la permeabilitat de la barrera epitelial pulmonar. El tràfic és una font important de contaminació. Es requereixen eines adequades per a mesurar la seva exposició. La contaminació del tràfic es un factor de risc important per a la salut respiratòria. / La contaminación atmosférica es un problema de salud pública, causa 380 000 muertes anuales en la Unión Europea. Esta tesis tiene como objetivo evaluar la exposición a la contaminación debida al tráfico y sus efectos en la salud respiratoria. Los niveles diarios de carbón y sulfuro medidos centralmente son buenos indicadores de exposición personal en una ciudad mediterránea, para PM2.5 fuentes de emisión alternas se tienen que considerar. La molestia debida a la contaminación no es un marcador de exposición, pero es importante porque refleja las percepciones individuales. La contaminación proveniente del tráfico aumento los síntomas del asma, y probablemente también causa asma en adultos. El PM2.5 proveniente de la combustión aumenta la permeabilidad de la barrera epitelial pulmonar. El tráfico es una fuente importante de la contaminación. Herramientas adecuadas para medir su exposición son requeridas. La contaminación del tráfico es un factor de riesgo importante para la salud respiratoria. / Air pollution is a major public health concern causing annually 380 000 deaths in the European Union. This thesis aims to study traffic-related air pollution exposure assessment and its association with respiratory effects. Daily levels of carbon and sulphur of outdoor central measurements are good surrogates for personal exposure in a Mediterranean setting; for PM2.5 other sources have to be taken into account. Annoyance due to air pollution is not a valid maker of air pollution exposure but is valuable in its own right as it integrates individual perceptions. Traffic-related air pollution increases asthma symptoms in adults and an association with new asthma onset is suggested. Furthermore, PM2.5 from combustion might lead to an increase in the lung's epithelial barrier permeability. Traffic-related air pollution is a major source of pollution. Adequate tools to assess its exposure are still needed. Traffic-related air pollution is an important risk factor for respiratory morbidity.

Poor air quality has been projected to be the world’s top cause of environmental premature mortality by 2050 surpassing poor sanitation and dirty water (IGBP / IGAC press release, 2012 ). One of the major challenges of air quality management is how to adequately quantify both the spatial and temporal variations of pollutants for the purpose of implementing necessary mitigation measures. The work described in this thesis aims to address this problem using novel electrochemical based air quality (AQ) sensors. These instruments are shown to provide cost effective, portable, reliable, indicative measurements for urban air quality assessment as well as for personal exposure studies. Three principal pollutants CO, NO and NO2 are simultaneously measured in each unit of the AQ instrument including temperature / RH measurements as well as GPS (for time and position) and GPRS for data transmission. Laboratory studies showed that the electrochemical sensor nodes can be highly sensitive, showing linear response during calibration tests at ppb level (0-160 ppb). The instrumental detection limits were found to be < 4 ppb (CO and NO) and < 1 ppb for NO2 with fast response time equivalent to t90 < 20 s. Several field studies were carried out involving deployment of both the mobile and static electrochemical sensor nodes. Results from some short-term studies in four different cities including Cambridge (UK), London (UK), Valencia (Spain) and Lagos (Nigeria) are presented. The measurements in these cities represent snapshot of the pollution levels, the stark contrast between the pollution level especially CO (mean mixing ratio of 16 ppm over 3 hrs) in Lagos and the other three cities is a reflection of the poor air quality in that part of the world. Results from long-term AQ monitoring using network of 46 static AQ sensors were used to characterise pollution in different environments ranging from urban to semi-urban and rural locations. By coupling meteorological information (wind measurements) with pollution data, pollution sources, and phenomena like the street canyon effect can be studied. Results from the long-term study also revealed that siting of the current fixed monitoring stations can fail to represent the actual air quality distribution and may therefore be unrepresentative. This work has shown the capability of electrochemical based AQ sensors in complementing the existing fixed site monitors thus demonstrating an emerging measurement paradigm for air quality monitoring and regulation, source attribution and human exposure studies.

No description available.

La sclérose en plaques (SEP) est une maladie neuro-inflammatoire du système nerveux central. Les causes sont multifactorielles impliquant à la fois une prédisposition génétique et l'influence de facteurs environnementaux. Dans environ 85% des cas, les patients sont atteints de poussées correspondants à la survenue de signes neurologiques, suivis d'une phase de rémission partielle ou totale. De nombreux travaux avancent l'hypothèse selon laquelle le taux de poussées varie au gré des saisons, survenant plus fréquemment au printemps et en été. Cette fluctuation temporelle a soulevé la question de l'influence de paramètres dépendants de la saison tels que l'ensoleillement et le statut en vitamine D, le niveau de mélatonine ou encore la pollution atmosphérique. Etant donné cette variation de la pollution de l'air, nous avons cherché à explorer l'impact à court terme des particules fines (PM10), benzène (C6H6), dioxyde d'azote (NO2), monoxyde de carbone (CO) et de l'ozone troposphérique (O3), sur le risque de déclenchement de poussée, indépendamment des saisons "chaude" (1er avril au 30 septembre) et "froide" (1er octobre au 31 mars). Ce travail s'est appuyé sur les données de patients issus du réseau ville-hôpital alSacEP. Nous avons sélectionné 424 patients atteints de SEP à début rémittent et ayant connu un total de 1 783 poussées (2000-2009). Les niveaux journaliers de pollution, produits grâce au modèle physique déterministe ADMS-Urban, ont été modélisés sur une base horaire pour chaque IRIS de la communauté urbaine de Strasbourg par l'actuelle AASQUA ATMO Grand Est. De plus, une enquête individuelle menée dans le cadre de cette étude auprès de l'ensemble des patients (PT) a permis de collecter (par questionnaire téléphonique ou auto-questionnaire sur internet) des informations personnelles socio-économiques (SES) et du mode de vie pour 188 d'entre eux (PS). Enfin, le niveau SES des IRIS a été estimé à l’aide d’un indice de défaveur social - construit à partir des données du recensement de l’INSEE. Nous avons observé une influence saisonnière délétère à court terme de la pollution (3 jours précédant la poussée) sur le risque de poussée en PT, notamment de l'O3 en saison "chaude" et des PM10 et NO2 en saison "froide". Nos résultats suggèrent également que le contexte SES puisse exacerber ces associations, notamment chez les patients résidant dans les quartiers défavorisés lors d'exposition aux PM10, NO2, C6H6 et CO ("froide") et ceux résidant dans les quartiers favorisés et défavorisés lors de l'exposition à l'O3 ("chaude"). Enfin, nous avons observé chez la PS que le niveau d'éducation faible, le revenu familial moyen, la consommation de cigarette et le manque d'activité physique régulière sont les catégories SES et du mode de vie les plus associées avec le risque de poussée lors de l'exposition à la pollution de l'air. Ce travail montre la nécessité d'étudier les expositions environnementales au cours de la SEP selon une approche holistique intégrant des facteurs individuels et contextuels. / Multiple sclerosis (MS) is a neuro-inflammatory disease of the central nervous system (CNS). Causes are multifactorial enrolling both genetic predisposition and influence of environmental factors. In 85% of cases, patients experience relapse corresponding to the occurrence of neurologic signs, followed by a phase of partial or total remission. Several studies put forth the hypothesis that relapses rate varies across season, mainly occurring during spring and summer. This temporal fluctuation raised the question of season-dependent parameters influence such as sunlight exposure and vitamin D, melatonin level or ambient air pollution. Considering this variation of air pollution, we explored the short-term impact of fine particles (PM10), benzene (C6H6), nitrogen dioxide (NO2), carbon monoxide (CO) and ground-level ozone (O3), on the risk of relapse triggering, separately for "cold" (i.e., October-March) and "hot" (April-September) season. This work has drawn from data of patients provided by the alSacEP network. We included 424 patients affected with remitting MS onset who experienced 1,783 relapses over the 2000-2009 period. Daily level of air pollution was modeled through ADMS-Urban software at the census block scale of the Strasbourg metropolitan area (AASQA ATMO Grand Est). Furthermore, an individual survey was conducted among all the patients (PT) in order to collect individual socioeconomic (SES) and lifestyle features. Finally, the census block SES position was estimated using a composite deprivation index - created from the INSEE census data. A short-term (3 days preceding the relapse) seasonal adverse effect was observed in PT, in particular during exposure to O3 in "hot" season and PM10 and NO2 in "cold" season. Results also suggest that the SES context might exacerbate these associations, in particular among patients who were living in deprived neighborhood with exposure to PM10, NO2, C6H6 and CO ("cold) and those who were living in most well-of and deprived places with exposure to O3 ("hot"). Finally, we observed among Ps that low education level, average family income, smoking and lack of physical activity are more associated with the risk of relapse triggering when patients were exposed to air pollution. This work shows the need to investigate environmental exposure such as air pollution along the SEP course using a holistic approach integrating individual and contextual factors.

L'oxydation et l'auto-inflammation de quatre carburants issus de la biomasse ont été étudiées dans des réacteurs adaptés à leurs réactivités, à haute pression et dans un large domaine de température. L'auto-inflammation du biogaz purifié (CH4 + H2) et du gaz de synthèse (CO + H2) a été étudiée en tube à choc à 10 bar entre 1200 et 2000 K. Elle se fait en un seul stade sans coefficient négatif de température ni de flamme froide. La cinétique d'oxydation du méthanol a été étudiée dans un réacteur parfaitement agité à 10 bar entre 700 et 1200 K. L'influence des oxydes d'azote (NOx) sur la cinétique d'oxydation du méthanol a également été étudiée. En présence de NOx l'oxydation du méthanol est accélérée. L'analyse et la quantification des produits de combustion ont permis de construire et de valider un modèle thermocinétique composé de 39 espèces et 170 réactions. L'oxydation et l'auto-inflammation du diméthyléther ont été étudiées en machine à compression rapide de 600 à 900 K et de 1,7 à 8,3 bar. L'effet de NO2 sur l'oxydation du diméthyléther a également été étudié. La formation de méthanoate de méthyle a été mise en évidence durant ce travail. Le diméthyléther présente une phénoménologie d'autoinflammation en deux stades avec coefficient négatif de température et flammes froides. Les délais d'autoinflammation mesurés en présence de NO2 sont plus courts. La base de données expérimentales établie à partir des résultats de cette étude a permis de mettre à jour un modèle thermocinétique de l'oxydation et de l'autoinflammation du diméthyléther. Le nouveau modèle a été validé sur des mesures obtenues en machine à compression rapide, tube à choc et réacteur parfaitement agité.