Tesis sobre el tema "Origines des aérosols"
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Bressi, Michael. "Les aerosols fins en Ile-de-France : chimie, sources et origines géographiques". Versailles-St Quentin en Yvelines, 2012. http://www.theses.fr/2012VERS0042.
This PhD thesis aims at documenting the chemical composition, the sources and the geographical origins of fine aerosols in the region of Paris, on an extended spatial and temporal scale. Five sampling sites -urban, suburban and rural- covering the entire region were used to sample PM2. 5 on a daily basis for one year. Major chemical compounds and source tracers were analysed. Statistical tools allowed the sources and the geographical origins of PM2. 5 to be determined, based on their chemical composition and back-trajectories analyses, respectively. Unexpectedly, PM2. 5 levels measured in Paris are amongst the lowest in Europe due to the flat orography of the region favouring the dispersion of pollutants. Aerosol pollution events were primarily due to the import of secondary aerosols -resulting from gas to particle conversion- stemming from Continental Europe. On the other hand, local sources (mainly biomass burning and road transport) only contribute a quarter of PM2. 5 levels on an annual scale
Velazquez, Garcia Alejandra. "Chemical and optical properties of particulate pollution in the Lille area, Northern France based on ATOLL observations". Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Lille Douai, 2023. http://www.theses.fr/2023MTLD0001.
The link between fine aerosol optical properties and their chemical composition is not yet well understood, and was investigated using long-term in situ observations performed at the “ATmospheric Observations in liLLe” platform from 2016 to 2020 using a combination of aerosol mass spectrometer, aethalometer, and nephelometer. Highly absorbing aerosols and a marked seasonality of the mass contribution of ammonium nitrate (AN) in spring were observed. We evidence that AN (35%) and carbonaceous aerosols (51%) are predominant regarding light extinction at 525 nm. Besides, a novel approach combining these in situ measurements to backtrajectories and emission inventories identifies a Brown Carbon (BrC) decrease within 24 hours after emission even during wintertime, pointing at a likely systematic underestimation of the contribution of residential heating (identified by the presence of BrC) to the aerosol absorption in the region
Val, Stéphanie. "Réponses de l'épithélium respiratoire à des particules atmosphériques de tailles et origines différentes : mécanismes moléculaires et cellulaires mis en jeu". Paris 7, 2011. http://www.theses.fr/2011PA077126.
Atmospheric particle (PM) exposure induces airway inflammation and is suspected to exacerbate chronic obstructive respiratory diseases that exhibit mucus overproduction. The aim of this study was (1) to identify physico-chemical characteristics of PM implicated in biological effects using ultrafine (UF), fine (F) and coarse (C) fractions of five different aerosols (2 French and 3 African) and (2) to deepen the mechanisms of mucin induction by PM on human bronchial epithelial cells in vitro. Whatever the aerosol, UF and F PM are the more reactive on a panel of biomarkers that are mostly sensitive to oxidative stress. These effects are associated to organic components of PM. Moreover, we demonstrated that PM. ₂,₅ induce expression and production of MUC5AC, a bronchial mucin, in in vitro conditions as well as in vivo in intratracheally instilled mice. MUC5AC induction results on EGF receptor activation by AREG, an EGFR ligand whose release is induced by PM demonstrating an autocrine effect. This work showed that finest fractions of PM have a high reactivity, which is in accordance with the new regulations limiting PM₂,₅ emissions. Furthermore, we demonstrated for the first time MUC5AC mechanisms of induction by PM, suggesting their implication in respiratory obstructive disease aggravation
Fleury, Benjamin. "La haute atmosphère de la Terre primitive, une source de composés organiques prébiotiques". Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLV012/document.
The origin of the organic matter on the early Earth is an important subject of research in planetology. This thesis presents an experimental study of the formation of organic compounds in the atmosphere of the early Earth investigating the reactivity of gaseous mixtures majority made of N2 and CO2. They present an important reactivity highlighted by the formation of gaseous products and solid products called tholins. The formation of these products points out CO2 as an efficiency source of carbon for the organic atmospheric growth. The identification of the gaseous products and the elemental analysis of the tholins showed a composition by C, N, H and O highlighting an efficiency coupling between the chemistry of these elements necessary for the formation of prebiotic compounds. This type of study have been applied then toTitan, which have a more reduced atmosphere, made of N2 and CH4, but, which contained also oxygenated trace species: principally CO. The addition of CO in the reactive medium involves also a coupling between the chemistry of O and the C, N, H chemistry currently considered for Titan. Finally I propose and investigate experimentally two phenomena, which may involve a chemical evolution of the aerosols of Titan during their sedimentation to the surface. First, an exposition of tholins to VUV photons, characteristic of the thermosphere of Titan, involves a selective depletion of amines function in favor of aliphatic functions. Second, an irradiation by UV photons of condensed species at the surface of tholins involves a reactivity of the solid species in interaction with the tholins, changing their chemical composition
Basile, Isabelle. "Origine des aérosols volcaniques et continentaux de la carotte de glace de Vostok (Antarctique)". Phd thesis, Grenoble 1, 1997. http://tel.archives-ouvertes.fr/tel-00756041.
Basile, Isabelle. "Origine des aérosols volcaniques et continentaux de la carotte de glace de Vostok (Antarctique)". Phd thesis, Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10170.
Bonnet, Sophie. "Le fer d' origine atmosphérique en milieu océanique oligotrophe". Paris 6, 2005. http://www.theses.fr/2005PA066481.
Petit, Jean-Eudes. "Compréhension des sources et des processus de formation de la pollution particulaire en région Ile-de-France". Electronic Thesis or Diss., Versailles-St Quentin en Yvelines, 2014. http://www.theses.fr/2014VERS0034.
Roig, Rodelas Roger. "Chemical characterization, sources and origins of secondary inorganic aerosols measured at a suburban site in Northern France". Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1R017/document.
Tropospheric fine particles with aerodynamic diameters less than 2.5 µm (PM2.5) may impact health, climate and ecosystems. Secondary inorganic (SIA) and organic aerosols (OA) contribute largely to PM2.5. To understand their formation and origin, a 1-year campaign (August 2015 to July 2016) of inorganic precursor gases and PM2.5 water-soluble ions was performed at an hourly resolution at a suburban site in northern France using a MARGA 1S, complemented by mass concentrations of PM2.5, Black Carbon, nitrogen oxides and trace elements. The highest levels of ammonium nitrate (AN) and sulfate were observed at night in spring and during daytime in summer, respectively. A source apportionment study performed by positive matrix factorization (PMF) determined 8 source factors, 3 having a regional origin (sulfate-rich, nitrate-rich, marine) contributing to PM2.5 mass for 73-78%; and 5 a local one (road traffic, biomass combustion, metal industry background, local industry and dust) (22-27%). In addition, a HR-ToF-AMS (aerosol mass spectrometer) and a SMPS (particle sizer) were deployed during an intensive winter campaign, to gain further insight on OA composition and new particle formation, respectively. The application of PMF to the AMS OA mass spectra allowed identifying 5 source factors: hydrocarbon-like (15%), cooking-like (11%), oxidized biomass burning (25%), less- and more-oxidized oxygenated factors (16% and 33%, respectively). Combining the SMPS size distribution with the chemical speciation of the aerosols and precursor gases allowed the identification of nocturnal new particle formation (NPF) events associated to the formation of SIA, in particular AN
Roig, Rodelas Roger. "Chemical characterization, sources and origins of secondary inorganic aerosols measured at a suburban site in Northern France". Electronic Thesis or Diss., Université de Lille (2018-2021), 2018. http://www.theses.fr/2018LILUR017.
Tropospheric fine particles with aerodynamic diameters less than 2.5 µm (PM2.5) may impact health, climate and ecosystems. Secondary inorganic (SIA) and organic aerosols (OA) contribute largely to PM2.5. To understand their formation and origin, a 1-year campaign (August 2015 to July 2016) of inorganic precursor gases and PM2.5 water-soluble ions was performed at an hourly resolution at a suburban site in northern France using a MARGA 1S, complemented by mass concentrations of PM2.5, Black Carbon, nitrogen oxides and trace elements. The highest levels of ammonium nitrate (AN) and sulfate were observed at night in spring and during daytime in summer, respectively. A source apportionment study performed by positive matrix factorization (PMF) determined 8 source factors, 3 having a regional origin (sulfate-rich, nitrate-rich, marine) contributing to PM2.5 mass for 73-78%; and 5 a local one (road traffic, biomass combustion, metal industry background, local industry and dust) (22-27%). In addition, a HR-ToF-AMS (aerosol mass spectrometer) and a SMPS (particle sizer) were deployed during an intensive winter campaign, to gain further insight on OA composition and new particle formation, respectively. The application of PMF to the AMS OA mass spectra allowed identifying 5 source factors: hydrocarbon-like (15%), cooking-like (11%), oxidized biomass burning (25%), less- and more-oxidized oxygenated factors (16% and 33%, respectively). Combining the SMPS size distribution with the chemical speciation of the aerosols and precursor gases allowed the identification of nocturnal new particle formation (NPF) events associated to the formation of SIA, in particular AN
Petit, Jean-Eudes. "Compréhension des sources et des processus de formation de la pollution particulaire en région Ile-de-France". Thesis, Versailles-St Quentin en Yvelines, 2014. http://www.theses.fr/2014VERS0034/document.
Gérard, Violaine. "Surfactants in atmospheric aerosols and their role on cloud formation". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1216/document.
Clouds are essential components of the Earth’s hydrological system and climate but some aspects of their formation are still not completely understood. In particular, although Köhler theory predicts that surfactants should enhance cloud droplet activation, current models consider this role negligible. At the time of this PhD work, a few studies had started to demonstrate the contrary but atmospheric evidence for the role of these compounds was still missing and very little was known about their atmospheric concentrations, sources, and mechanism of action. The objective of this PhD work was to investigate these aspects. A method was developed to quantify surfactant concentrations in aerosols. Its application led to the first absolute atmospheric surfactants’ surface tension curves, in coastal PM2.5 aerosols in Sweden, and to the identification of the ratio C/CMC as the key parameter controlling the cloud-forming efficiency of aerosols. A second study revealed strong correlations between cloud occurrence and intrinsic surfactant properties in boreal PM1 aerosols in Finland, demonstrating for the first time the role of surfactants in cloud formation from direct atmospheric observations. The results predicted Cloud Condensation Nuclei numbers four times larger on average than when neglecting surfactant effects, showing the importance of including surfactant effects in cloud predictions models. The role of surfactants inferred from macroscopic measurements was confirmed by laboratory experiments on individual micron-sized droplets showing an increase of droplet growth in the presence of surfactants. Finally, observations from the different field studies indicated a biological origin for the surfactants present in atmospheric aerosols
Barros, de Oliveira Diogo Miguel. "Identification of the main sources and geographical origins of PM10 in the northern part of France". Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10007/document.
Airborne particles have significant economical, health and environmental impacts at a global scale. Mitigating their emissions to improve ambient air quality demands a deep knowledge on their sources, which can be determined by investigating their chemical composition. The present thesis aims at identifying major PM10 sources and geographical origins at 5 sampling sites (3 urban background, 1 traffic and 1 remote) representative of Northern France, which is frequently submitted to exceedances of limit values as defined by European Directives. The first step of this study included a comprehensive chemical characterization of PM10 filter samples collected every third day at the 5 sites. Organic matter and ammonium nitrate were confirmed as the main PM10 species in the investigated area with some differences according to the site type. Positive Matrix Factorization (PMF) was used to identify and quantify the contributions of primary sources as well as secondary processes impacting each sampling site. Large contributions of secondary aerosols (mainly grouped as nitrate-, sulfate- and oxalate-rich aerosols) were obtained at all sites, as well as significant traffic and biomass burning. The use of specific tracers like MSA and polyols also proved to be useful to identify marine and continental biogenic aerosols, respectively. Statistical trajectory-based model was applied to PMF outputs to calculate Concentration Field maps and locate emission sources of marine particles, namely fresh and aged sea salts (primarily from the Atlantic Ocean) and marine biogenic aerosols (mainly from the North Sea), as well as continental contributions of nitrate-and sulfate-rich secondary particles
Duca, Dumitru. "Physico-chemical characterization of size-selected internal combustion engine nanoparticles and original method for measuring adsorption energies on carbonaceous surfaces by laser mass spectrometry". Thesis, Lille 1, 2020. http://www.theses.fr/2020LIL1R019.
Emission of carbonaceous aerosols by combustion-powered ground transport vehicles has a major impact on both global climate and human health. Intensive research efforts are dedicated to the development of robust procedures able to reliably measure particles as small as 10 nm in real-driving conditions, as current European Union regulations are limited to 23 nm. Within the H2020 PEMS4Nano project, we performed detailed physico-chemical characterization of size-selected particulate matter emitted by a gasoline direct injection engine. This included chemical characterization performed with mass spectrometry as well as structural/morphology data obtained with electron and atomic force microscopy together with Tip-Enhanced Raman Spectroscopy. In addition, to gain insight into the interaction between the carbonaceous surface and adsorbed compounds, a novel laser-based method for determining the adsorption energy of chemical species on carbonaceous surfaces was developed
Duca, Dumitru. "Physico-chemical characterization of size-selected internal combustion engine nanoparticles and original method for measuring adsorption energies on carbonaceous surfaces by laser mass spectrometry". Electronic Thesis or Diss., Université de Lille (2018-2021), 2020. http://www.theses.fr/2020LILUR019.
Emission of carbonaceous aerosols by combustion-powered ground transport vehicles has a major impact on both global climate and human health. Intensive research efforts are dedicated to the development of robust procedures able to reliably measure particles as small as 10 nm in real-driving conditions, as current European Union regulations are limited to 23 nm. Within the H2020 PEMS4Nano project, we performed detailed physico-chemical characterization of size-selected particulate matter emitted by a gasoline direct injection engine. This included chemical characterization performed with mass spectrometry as well as structural/morphology data obtained with electron and atomic force microscopy together with Tip-Enhanced Raman Spectroscopy. In addition, to gain insight into the interaction between the carbonaceous surface and adsorbed compounds, a novel laser-based method for determining the adsorption energy of chemical species on carbonaceous surfaces was developed
Delmonte, Barbara. "Origine et variation des concentrations et distributions des poussières d'origine continentale dans les forages de glace en Antarctique". Phd thesis, 2003. http://tel.archives-ouvertes.fr/tel-00701343.