Dissertationen zum Thema „Aerosol origins“

Thesis (Ph. D.)--University of Maryland, College Park, 2004.
Thesis research directed by: Chemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

Le lien entre les propriétés optiques des aérosols fins et leur composition chimique n'est pas encore bien compris. Il a été étudié ici en utilisant des mesures in situ (spectromètre de masse d'aérosol, aethalomètre et néphélomètre) réalisées sur la plateforme ‘ATmospheric Observations in liLLe’ de 2016 à 2020. On a pu observer des aérosols très absorbants et une saisonnalité marquée pour la contribution massique du nitrate d'ammonium (AN) au printemps. Nous avons montré que l'AN (35%) et les aérosols carbonés (51%) prédominent dans l’extinction du rayonnement à 525 nm. Enfin, une nouvelle approche combinant ces mesures in situ à des rétrotrajectoires, et des inventaires d'émissions ont révélé une diminution du carbone brun (BrC) dans les 24 heures suivant son émission, même en hiver, ce qui implique une probable sous-estimation systématique de la contribution attribuée au chauffage résidentiel (lié à la présence de BrC) dans l'absorption des aérosols de la région
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

The development of industry, transport, agriculture and power engineering inevitably create problems related to the impact of generated waste on the environment as well as other undesirable processes. The atmosphere is the main component of the Earth’s climate system because changes occurring due to the human economic activity result in serious environmental impacts in all components of the ecosystem as well as the Earth’s climate self-regulation system is disturbed. The objective of this work was to investigate the origin, sources and formation of organic compounds and black carbon in atmospheric aerosol particles and to develop new research methods. To attain this objective the following tasks have been formulated: Development of the identification method for the aerosol origin and source by investigating the carbon isotope mass ratios, illustration of possibilities of the carbon isotope ratio method by identifying the aerosol particle origin during the air mass long-range transport at the Preila Environmental pollution research station, investigation of variation of the black carbon amount in aerosol particles in the diesel engine exhaust depending on the engine working parameters and fuel composition, investigation of the carbon isotope ratio variation in natural aerosol depending on the aerosol particle size distribution, determination of the partial contribution of natural and anthropogenic particles in aerosol by investigation of stable carbon and radiocarbon isotope... [to full text]
Žemės atmosfera yra svarbiausia klimato sferos dalis ir jautriausias antropogeninei taršai aplinkos sandas. Atmosferoje vykstantys procesai pakeičia ekosistemose per šimtmečius nusistovėjusius procesus – stebime įvairias globalinės klimato kaitos sukeltas pasekmes. Mokslinė šio darbo idėja nukreipta į įvairiapusį atmosferos aerozolio dalelių savybių ir prigimties tyrimą bei tyrimo metodų plėtrą, pasiremiant naujausiomis aplinkotyros mokslo žiniomis, akcentuojant pastarojo dešimtmečio masių spektrometrijos pasiekimus. Šio darbo tikslas yra organinių medžiagų ir juodosios anglies atmosferos aerozolio dalelėse kilmės, aerozolio sudėties ir formavimosi tyrimai bei naujų tyrimo metodų plėtra. Darbe eksperimentiškai įrodyta, kad anglies izotopų santykis antropogeninės kilmės aerozolio dalelėse atitinka deginamo kuro izotopų santykį ir šis parametras tinka, identifikuojant aerozolio dalelių šaltinį. Šis izotopų santykis, kaip metodinė priemonė, buvo panaudotas tiriant įvairios prigimties aerozolio sudėtį, savybes ir kilmę. Tiriant aerozolio daleles tolimojoje oro pernašoje stebėjome elementinės anglies δ13C verčių kaitą akumuliacinėje modoje nuo -22,9 ‰ iki -26,3 ‰, organinės anglies δ13C = -28 ‰. Iš δ13C verčių nustatyta, jog elementinės anglies pirmtakai aerozolio dalelėse buvo degimo produktai, organinės anglies šaltinis – lakūs organiniai junginiai iš augalų. Vietinės kilmės dalelių, didesnių už 1 μm, stebėta karbonatinė komponentė. Apjungus masių ir izotopų santykių masių... [toliau žr. visą tekstą]

The objective of the work was to investigate physical and chemical properties and sources of the atmospheric aerosol particles in the submicron fraction by combining different analytical techniques. The dependence of concentrations of organic and elemental carbon in different air masses was determined and the contribution of regional and local sources to the net aerosol particle pollution was estimated. Analysis of the size distribution of carbonaceous aerosol particles in background and urban areas was performed. Biogenic organic aerosol made up 15 % of the organic aerosol mass at the Preila atmospheric pollution research station, but in the North Atlantic air masses this factor was up to 50 %. Aerosol and stable isotope ratio mass spectrometry has revealed that traffic is the primary source of aerosol particles in the city, while biomass burning is the primary source at the Rūgšteliškis background station. It was determined that secondary anthropogenic organic compounds were dominating (76 %) in Vilnius, while in Rūgšteliškis secondary biogenic organic compounds made up 50 % of the total organic aerosol mass. The influence of the long-range air mass transport on the local origin aerosol particle formation and transformation has been evaluated and it has been shown that volcanic aerosol particles can significantly change the concentration, chemical composition and size distribution of local aerosol particles in the submicron range.
Disertacija skirta smulkiosios aerozolio dalelių frakcijos šaltinių, fizikinių ir cheminių savybių įvertinimui kompleksiškai apjungiant įvairius tyrimo metodus. Darbe susieti elementinės ir organinės anglies koncentracijų pokyčiai su tolimąja oro masių pernaša, įvertinta regiono bei vietinių šaltinių įtaka bendrai aerozolio dalelių taršai. Aprašyti anglies turinčių aerozolio dalelių pasiskirstymai pagal dydį foninėse vietovėse ir miesto aplinkoje. Naudojant aerozolio masių spektrometrą Preilos atmosferos užterštumo tyrimų stotyje buvo identifikuotas biogeninis organinių medžiagų šaltinis, kuris vidutiniškai sudaro 15 % nuo organinių medžiagų masės, tačiau Šiaurės Atlanto oro masėje biogeninių medžiagų indėlis siekia net 50 %. Atlikus kompleksinę aerozolio ir stabiliųjų anglies izotopų masių spektrometrinę analizę buvo nustatyta, kad pirminis anglies turinčio aerozolio dalelių šaltinis mieste yra autotransportas, o Rūgšteliškio foninėje vietovėje – biomasės deginimas. Taip pat buvo nustatyta, kad Vilniuje dominavo antropogeninės antrinės organinės medžiagos (76 %), o Rūgšteliškyje vyravo biogeninės antrinės organinės medžiagos (apie 50%). Vertinant tolimosios oro masių pernašos įtaką vietinės kilmės aerozolio dalelių formavimuisi ir kaitai, buvo nustatyta, kad vulkaninės kilmės aerozolio dalelės turi įtakos submikroninės aerozolio dalelių frakcijos koncentracijai, cheminei sudėčiai ir pasiskirstymui pagal dydį.

The main objective of this thesis was the chemical characterization of synthetic secondary organic aerosol (SOA) produced from atmospherically relevant anthropogenic and biogenic VOCs during reaction chamber experiments. In parallel, the resulting chemical features of these laboratory-SOA were used to interpret the composition of ambient samples of atmospheric fine particulate matter collected at several sites in Europe, in order to determine the fraction of ambient aerosol organic mass accounted for by biogenic and anthropogenic SOA.

The main objective of this thesis was the chemical characterization of synthetic secondary organic aerosol (SOA) produced from atmospherically relevant anthropogenic and biogenic VOCs during reaction chamber experiments. In parallel, the resulting chemical features of these laboratory-SOA were used to interpret the composition of ambient samples of atmospheric fine particulate matter collected at several sites in Europe, in order to determine the fraction of ambient aerosol organic mass accounted for by biogenic and anthropogenic SOA.

Les nuages sont essentiels dans le cycle de l'eau et dans le budget climatique mais certains aspects de leur formation sont encore incompris. La théorie de Köhler prédit que les surfactants devraient favoriser l'activation des particules en goutte de nuage alors que les modèles actuels les considèrent comme négligeables. Au début de ce travail de thèse, quelques études commençaient à démontrer le contraire mais des preuves du rôle de ces composés dans l'atmosphère étaient encore manquantes, d'où l'objectif de ce travail de thèse. Le développement d'une méthode pour déterminer la concentration en surfactants dans les aérosols a conduit aux premières courbes de tension de surface de surfactants atmosphériques dans des aérosols PM2.5 côtiers (Suède), et à l'identification du ratio C/CMC comme paramètre clé contrôlant l'efficacité des aérosols à former des nuages. Une seconde étude a révélé des corrélations fortes entre la présence de nuages et les propriétés intrinsèques des surfactants dans des aérosols PM1 boréaux (Finlande), démontrant pour la première fois le rôle des surfactants dans la formation des gouttes de nuage à partir d'observations directes dans l'atmosphère. Les résultats prédisent un nombre de noyaux de condensation en moyenne quatre fois plus important que lorsque les effets des surfactants étaient négligés, montrant l‘importance d'inclure l'effet des surfactants dans les modèles prédictifs. Cette importance a été confirmée en laboratoire par des expériences sur des gouttes individuelles microniques par l'augmentation de leur taille en présence de surfactants. Enfin, les observations à partir des différentes études indiquent une origine biologique des surfactants dans les aérosols atmosphériques
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

Cette thèse se propose de documenter la composition chimique, les sources et les origines géographiques des aérosols fins (PM2. 5) en Ile-de-France (IdF), sur une échelle spatio-temporelle étendue. Cinq sites de mesures -urbains, suburbains et ruraux- couvrant l'ensemble de cette région ont été utilisés pour prélever les PM2. 5 quotidiennement pendant une année. Les fractions chimiques majeures et des traceurs de sources ont été analysés. Des outils statistiques ont permis de déterminer les sources des PM2. 5 à partir de leur composition chimique, et leurs origines géographiques à partir de rétro-trajectoires de masses d'air. De manière inattendue, les niveaux de PM2. 5 observés sur Paris sont parmi les plus faibles en Europe, du fait de l'orographie plate de la région IdF favorable à la dispersion des polluants. Les épisodes de pollution particulaire sont majoritairement dus à de l'import de particules secondaires -résultant de la condensation d'espèces gazeuses- provenant d'Europe continentale. A l'inverse, les sources locales (combustion de biomasse et transport routier principalement) ne contribuent qu'à un quart des niveaux mesurés à l'échelle de l'année
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

Disertacija skirta smulkiosios aerozolio dalelių frakcijos šaltinių, fizikinių ir cheminių savybių įvertinimui kompleksiškai apjungiant įvairius tyrimo metodus. Darbe susieti elementinės ir organinės anglies koncentracijų pokyčiai su tolimąja oro masių pernaša, įvertinta regiono bei vietinių šaltinių įtaka bendrai aerozolio dalelių taršai. Aprašyti anglies turinčių aerozolio dalelių pasiskirstymai pagal dydį foninėse vietovėse ir miesto aplinkoje. Naudojant aerozolio masių spektrometrą Preilos atmosferos užterštumo tyrimų stotyje buvo identifikuotas biogeninis organinių medžiagų šaltinis, kuris vidutiniškai sudaro 15 % nuo organinių medžiagų masės, tačiau Šiaurės Atlanto oro masėje biogeninių medžiagų indėlis siekia net 50 %. Atlikus kompleksinę aerozolio ir stabiliųjų anglies izotopų masių spektrometrinę analizę buvo nustatyta, kad pirminis anglies turinčio aerozolio dalelių šaltinis mieste yra autotransportas, o Rūgšteliškio foninėje vietovėje – biomasės deginimas. Taip pat buvo nustatyta, kad Vilniuje dominavo antropogeninės antrinės organinės medžiagos (76 %), o Rūgšteliškyje vyravo biogeninės antrinės organinės medžiagos (apie 50%). Vertinant tolimosios oro masių pernašos įtaką vietinės kilmės aerozolio dalelių formavimuisi ir kaitai, buvo nustatyta, kad vulkaninės kilmės aerozolio dalelės turi įtakos submikroninės aerozolio dalelių frakcijos koncentracijai, cheminei sudėčiai ir pasiskirstymui pagal dydį.
The objective of the work was to investigate physical and chemical properties and sources of the atmospheric aerosol particles in the submicron fraction by combining different analytical techniques. The dependence of concentrations of organic and elemental carbon in different air masses was determined and the contribution of regional and local sources to the net aerosol particle pollution was estimated. Analysis of the size distribution of carbonaceous aerosol particles in background and urban areas was performed. Biogenic organic aerosol made up 15 % of the organic aerosol mass at the Preila atmospheric pollution research station, but in the North Atlantic air masses this factor was up to 50 %. Aerosol and stable isotope ratio mass spectrometry has revealed that traffic is the primary source of aerosol particles in the city, while biomass burning is the primary source at the Rūgšteliškis background station. It was determined that secondary anthropogenic organic compounds were dominating (76 %) in Vilnius, while in Rūgšteliškis secondary biogenic organic compounds made up 50 % of the total organic aerosol mass. The influence of the long-range air mass transport on the local origin aerosol particle formation and transformation has been evaluated and it has been shown that volcanic aerosol particles can significantly change the concentration, chemical composition and size distribution of local aerosol particles in the submicron range.

Les particules fines troposphériques de diamètre aérodynamique inférieur à 2,5 µm (PM2.5) peuvent impacter la santé et les écosystèmes. Les aérosols inorganiques secondaires (AIS) et organiques (AO) contribuent fortement aux PM2.5. Pour comprendre leur formation et leur origine, une campagne d’1 an (août 2015 - juillet 2016) de mesures horaires de gaz précurseurs inorganiques et d’ions hydrosolubles particulaires a été menée sur un site urbain du nord de la France avec un MARGA 1S, complétées par les concentrations massiques en PM2.5, carbone suie, oxydes d’azote et éléments traces. Des niveaux élevés de nitrate d’ammonium (NA) ont été observés la nuit au printemps et de sulfate d’ammonium la journée en été. L’étude de la contribution des sources par le modèle PMF (Positive Matrix Factorization) a permis d’identifier 8 facteurs sources: 3 régionaux (riche en sulfates, riche en nitrates et marin) pour 73 à 78%, et 5 locaux (trafic, combustion de biomasse, fond industriel métallurgique, industrie locale et poussières minérales) (22-27%). De plus, un HR-ToF-AMS (spectromètre de masse à aérosols) et un SMPS (granulomètre) ont été utilisés lors d’une campagne intensive en hiver, afin de mieux documenter l’AO et la formation de nouvelles particules, respectivement. L’application du PMF aux spectres de masses d’AO a permis d’identifier 5 facteurs liés au trafic (15%), à la cuisson (11%), à la combustion de biomasse (25%), et à une oxydation plus ou moins forte de la matière organique (33% et 16%). Plusieurs événements nocturnes de formation de nouvelles particules impliquant les AIS, notamment du NA, ont été observés
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

Les particules fines troposphériques de diamètre aérodynamique inférieur à 2,5 µm (PM2.5) peuvent impacter la santé et les écosystèmes. Les aérosols inorganiques secondaires (AIS) et organiques (AO) contribuent fortement aux PM2.5. Pour comprendre leur formation et leur origine, une campagne d’1 an (août 2015 - juillet 2016) de mesures horaires de gaz précurseurs inorganiques et d’ions hydrosolubles particulaires a été menée sur un site urbain du nord de la France avec un MARGA 1S, complétées par les concentrations massiques en PM2.5, carbone suie, oxydes d’azote et éléments traces. Des niveaux élevés de nitrate d’ammonium (NA) ont été observés la nuit au printemps et de sulfate d’ammonium la journée en été. L’étude de la contribution des sources par le modèle PMF (Positive Matrix Factorization) a permis d’identifier 8 facteurs sources: 3 régionaux (riche en sulfates, riche en nitrates et marin) pour 73 à 78%, et 5 locaux (trafic, combustion de biomasse, fond industriel métallurgique, industrie locale et poussières minérales) (22-27%). De plus, un HR-ToF-AMS (spectromètre de masse à aérosols) et un SMPS (granulomètre) ont été utilisés lors d’une campagne intensive en hiver, afin de mieux documenter l’AO et la formation de nouvelles particules, respectivement. L’application du PMF aux spectres de masses d’AO a permis d’identifier 5 facteurs liés au trafic (15%), à la cuisson (11%), à la combustion de biomasse (25%), et à une oxydation plus ou moins forte de la matière organique (33% et 16%). Plusieurs événements nocturnes de formation de nouvelles particules impliquant les AIS, notamment du NA, ont été observés
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

Deposes en antarctique de l'est au cours des 4 derniers cycles climatiques, les aerosols volcaniques (5-50 m) et continentaux (2-3 m) de la carotte de vostok constituent des traceurs de circulations atmospheriques pasees. Pour reconstruire leurs trajectoires tropospheriques, il est necessaire d'identifier leurs sources (volcans ou regions desertiques). Pour cela, on compare les caracteristiques geochimiques (elements majeurs microsonde electronique, traces icpms et compositions isotopiques tims) des aerosols avec les caracteristiques des sources potentielles repertoriees. Nous avons du adapter ces methodes analytiques a la taille des aerosols et a leur faible quantite. Les caracteristiques geochimiques des volcans sources s'appuient sur une synthese bibliographique. On montre que les cendres proviennent essentiellement de l'arc volcanique des iles sandwichs, mais aussi d'antarctique de l'ouest et d'amerique du sud. De plus, certains horizons sont des marqueurs stratigraphiques pour dater (141 ka) et correler les carottes. Les caracteristiques isotopiques (sr et nd) des regions desertiques d'afrique du sud, d'australie, d'amerique du sud, d'antarctique et de nouvelle zelande sont mesurees sur des echantillons preleves in situ. Il est necessaire d'utiliser, pour la comparaison avec les aerosols, la fraction granulometrique inferieure a 5 m. Il est montre que les poussieres continentales proviennent de la patagonie en periode interglaciaire (flux 1,5 mg/m#2/an) comme en glaciaire (20 mg/m#2/an). Une partie de cette augmentation de flux s'explique par la presence de vastes epandages de materiel detritique fluvio-glaciaire qui recouvrent en periode glaciaire la patagonie et le plateau continental argentin emerge. Les sources des aerosols sont donc localisees, quelle que soit la periode climatique, dans une region situee du cote atlantique de l'antarctique, aux moyennes et hautes latitudes. Le transport des particules est assure par un courant d'ouest circumpolaire convergent vers l'antarctique. Ce travail montre que, a partir des aerosols volcaniques et continentaux, on peut obtenir des paleo-informations dynamiques qui, au travers des correlations, des datations, ou des modeles de circulation atmospherique globaux, sont utiles aux reconstitutions des climats du passe.

Déposés en Antarctique de l'Est au cours des 4 derniers cycles climatiques, les aérosols volcaniques (5-50 )um) et continentaux (2-3 )um) de la carotte de Vostok constituent des traceurs de circulations atmosphériques passées. Pour reconstruire leurs trajectoires troposphériques, il est nécessaire d'identifier les sources (volcans ou régions désertiques) à l'origine des émissions des cendres et des poussières continentales. Pour cela, on compare les caractéristiques géochimiques des aérosols avec les caractéristiques des sources potentielles répertoriées. Ces analyses reposent sur les concentrations en éléments majeurs (obtenues par microsonde électronique), en éléments traces (ICPMS), et sur les compositions isotopiques en Strontium et Néodyme (TIMS). Nous avons dû adapter ces méthodes analytiques à la petite taille des aérosols et à leur très faible quantité. Les caractéristiques géochimiques des volcans sources potentiels (latitude>30oS, activité<-500 ka) sont basées sur une synthèse bibliographique. On montre que les cendres des horizons volcaniques analysés proviennent essentiellement de l'arc volcanique des îles Sandwichs (situé dans l'Atlantique Sud, à 5000 km), mais aussi d'Antarctique de l'Ouest et d'Amérique du Sud. De plus, certains horizons peuvent être utilisés comme marqueurs stratigraphiques pour dater (e.g. 141 ka) et corréler les carottes. Les caractéristiques isotopiques (Sr et Nd) des régions désertiques d'Afrique du Sud, d'Australie, du Sud de l'Amérique du Sud, d'Antarctique et de Nouvelle Zélande sont mesurées sur des échantillons prélevés in situ. On remarque qu'il est nécessaire d'utiliser, pour la comparaison avec les aérosols, la fraction granulométrique inférieure à 5 um. Il est ainsi montré que les poussières continentales déposées à Vostok au cours des 4 derniers cycles climatiques proviennent de la Patagonie en période interglaciaire (flux -1,5 mg/m2/an) comme en période glaciaire (flux -20 mg/m2/an). Une partie de cette augmentation de flux peut être expliquée par la présence de vastes épandages de particules détritiques fluvio-glaciaires qui recouvrent, en période glaciaire, la Patagonie et le plateau continental argentin émergé. L'ensemble des sources des aérosols volcaniques et continentaux est donc localisé, quelle que soit la période climatique, dans une région située du côté Atlantique de l'Antarctique, aux moyennes et hautes latitudes. Le transport des particules semble quant à lui être assuré par un courant d'ouest circumpolaire convergent versl'Antarctique. Ce travail montre donc que, à partir des aérosols volcaniques et continentaux, on peut obtenir des paléo-informations dynamiques qui, au travers des corrélations, des datations, ou des modèles de circulation atmosphérique globaux, seront utiles aux reconstitutions des climats du passé.

L’origine de la matière de la Terre primitive est un important sujet de recherche en planétologie. Cette thèse présente une étude expérimentale de la formation de composés organiques dans l’atmosphère de la Terre primitive en étudiant la réactivité de mélanges gazeux majoritairement composé de N2 et CO2. Ils présentent une importante réactivité se traduisant par la formation de produits gazeux et solides, appelés tholins. La formation de ces produits met en avant l’efficacité de CO2 comme source de carbone pour la croissance organique atmosphérique. L’identification des produits gazeux et l’analyse élémentaire des tholins ont montré qu’ils étaient constitués de C, N, H et O, soulignant un couplage efficace entre la chimie de ces éléments nécessaire à la formation de composés d’intérêts prébiotiques. Ce type d’étude a été appliqué ensuite à Titan qui a une atmophère plus réduite,faite de N2 et CH4, mais contient des traces d’espèces oxygénées, majoriatirement CO. L’ajout de CO au mélange réactif induit également un couplage entre la chimie de l’O et la chimie C, N, H considérée habituellement pour Titan. Enfin je propose et étudie expériemntalement deux phénomènes suseptibles de modifier la composition des aérosols de Titan durant leur sédimentation vers la surface. Premièrement une exposition de tholins aux photons VUV caractéristique de la thermosphère de Titan et qui induit une diminution sélective des fonctions amines en faveurs des fonctions aliphatiques. Deuxièmement une irradiation par des photons UV d’espèces condensées à la surface de tholins et qui induit une réactivité de l’espèce en interaction avec les tholins, modifiant sa composition chimique
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

Human activities such as mining and smelting of lead (Pb) ores and combustion of alkyllead additives in gasoline have resulted in extensive global Pb pollution. Since the late 1960's studies of polar ice and snow have been undertaken to evaluate the extent of anthropogenic Pb emissions in recent times as well as to investigate changes in anthropogenic Pb emissions in the more distant past. The polar ice sheets have been used to investigate Pb pollution as they offer a long-term record of human activity located far from pollution sources and sample aerosol emissions on a hemispheric scale. Lead isotopes have been previously used to identify sources of Pb in polar snow and ice, while new evaluations of Pb isotopic compositions in aerosols and Pb ore bodies allow more thorough evaluations of anthropogenic Pb emissions. Lead isotopic compositions and Pb and Barium (Ba) concentrations have been measured in snow and ice core samples from Law Dome, East Antarctica, to produce a detailed pollution history between 1530 AD and 1989 AD. Such a record has been produced to evaluate changes in anthropogenic Pb emission levels and sources over the past 500 years, to determine when industrial (anthropogenic) activities first began to influence Antarctica and also to investigate natural Pb fluxes to Antarctica. Additional samples were also collected from Law Dome snow and ice cores to respectively investigate seasonal variations in Pb and Ba deposition, and the influence of the 1815 AD volcanic eruption of Tambora, Indonesia. All samples were measured by thermal ionisation mass spectrometry, for which techniques were developed to reliably analyse Pb isotopic compositions in Antarctic samples containing sub-picogram per gram concentrations of Pb.Particular attention was given to the quantity of Pb added to the samples during the decontamination and sample storage stages of the sample preparation process. These stages, including the use of a stainless steel chisel for the decontamination, contributed ~5.2 pg to the total sample analysed, amounting to a concentration increase of ~13 fg g-1. In comparison, the mass spectrometer ion source contributed typically 89 +/- 19 fg to the blank, however its influence depended upon the amount of Pb available for analysis and so had the greatest impact when small volumes of samples with a very low concentration were analysed. As a consequence of these careful investigations of the Pb blank contributions to the samples, the corrections made to the Pb isotopic ratios and concentrations measured are smaller than previously reported evaluations of Pb in Antarctica by thermal ionisation mass spectrometry. The data indicate that East Antarctica was relatively pristine until -1884 AD, after which the first influence of anthropogenic Pb in Law Dome is observed. "Natural", pre-industrial, background concentrations of Pb and Ba were - 0.4 pg/g and - 1.3 pg/g, respectively, with Pb isotopic compositions within the range 206Pb/207Pb = 1.20 - 1.25 and 208Pb/207Pb = 2.46 - 2.50 and an average rock and soil dust Pb contribution of 8-12%. A major pollution event was observed at Law Dome between 1884 and 1908 AD, elevating the Pb concentration fourfold and changing 206Pb/207Pb ratios in the ice to ~1.12. Based on Pb isotopic systematics and Pb emissions statistics, this was attributed to Pb mined at Broken Hill and smelted at Broken Hill and Port Pirie, Australia.Anthropogenic Pb inputs to Law Dome were most significant from ~1900 to 1910 and from ~1960 to 1980. During the 20th century, Ba concentrations were consistently higher than "natural" levels. This was attributed to increased dust production, suggesting the influence of climate change and/or changes in land coverage with vegetation. Law Dome ice dated from 1814 AD to 1819 AD was analysed for Pb isotopes and Pb, Ba and Bismuth (Bi) concentrations to investigate the influence of the 1815 AD volcanic eruption of Tambora, Indonesia. The presence of volcanic debris in the core samples was observed from late-1816 AD to 1818 AD as an increase in sulphate concentrations and electrical conductivity of the ice. Barium concentrations were approximately three times higher than background levels from mid-1816 to mid1818, consistent with increased atmospheric loading of rock and soil dust, while enhanced Pb/Ba and Bi/Ba ratios, associated with deposition of volcanic debris, were observed at mid-1814 and from early-1817 to mid-1818. From the results, it appeared likely that Pb emitted from Tambora was removed from the atmosphere within the 1.6 year period required to transport aerosols to Antarctica. Increased Pb and Bi concentrations observed in Law Dome ice ~1818 AD were attributed to either increased heavy metal emissions from Mount Erebus, or increased fluxes of heavy metals to the Antarctic ice sheet resulting from climate and meteorological modifications following the Tambora eruption.A non-continuous series of Law Dome snow core samples dating from 1980 to 9185 AD were analysed to investigate seasonal variations in the deposition of Pb and Ba. It was found that Pb and Ba at Law Dome do exhibit seasonal variations in deposition, with higher concentrations of Pb and Ba usually observed during Summer and lower concentrations of Pb and Ba usually observed during the Autumn and Spring seasons. At Law Dome, broad patterns of seasonal Pb and Ba deposition are evident however these appear to be punctuated by short-term deposition events or may even be composed of a continuum of short-term deposition events. This variability suggests that complex meteorological systems are responsible for the transport of Pb and Ba to Law Dome, and probably Antarctica in general.

Introducción Un aerosol es una dispersión de sólidos o líquidos en un medio gaseoso. Las partículas de tamaño comprendido entre 0,1 um y 10 um tienden a formar suspensiones mecánicamente estables en el aire, por lo que reciben el nombre de partículas en suspensión. Estas partículas son las que mayores efectos presentan, ya que permanecen en la atmósfera y pueden ser trasladadas a grandes distancias por la acción del viento y son denominadas partículas PM10. Los aerosoles pueden tener un origen natural o antrópico (Querol et al., 2004; Brasseur et al., 1999) y su presencia en la atmósfera produce efectos negativos sobre la salud de las personas y de los animales (Cabasés et al., 2002), la visibilidad (Tsay et al., 1991), los materiales y el medio ambiente (Gaudichet et al., 1992). Por ello, la legislación actual establece unos límites de concentración de PM10 para asegurar la salud humana, así como unos valores límite en la concentración de los elementos arsénico, plomo, cadmio y níquel en dichas partículas PM10. La recirculación de los contaminantes debido a la dinámica convectiva de los vientos (Millán et al., 2000), unida a la intrusión de partículas procedentes del norte de África (Esteve et al., 1997; Castillo et al., 2008) y a las emisiones por parte de las industrias, producen niveles de concentración de contaminantes en la zona mediterránea de la Península Ibérica mayores que los medidos en países europeos con actividades industriales similares. El cluster cerámico de Castellón es un triángulo con más de 200 empresas vinculadas al sector cerámico (fritas, esmaltes, colorantes, azulejos, gres, gres porcelánico, canteras, atomizado, etc.). Dicho cluster concentra el 94,5% de la producción española de cerámica plana y el 38,5% de la de la Unión Europea. L'Alcora es un municipio perteneciente a la comarca de l'Alcalatén, principalmente industrial y en él se encuentra la mayor parte de las empresas dedicadas a la industria cerámica, incluyendo la fabricación de pavimentos y revestimientos, fritas y esmaltes, pigmentos y colorantes y plantas atomizadoras. Es el principal municipio perteneciente al cluster cerámico de la provincia de Castellón. Castellón de la Plana es la capital de la provincia de Castellón. Entre las múltiples empresas que desarrollan su actividad en esta ciudad, cabe destacar el polígono industrial de El Serrallo, situado en el Grao de Castellón de la Plana. En dicho polígono industrial cabe destacar tres empresas: la central termoeléctrica de Castellón, (actualmente desmantelada y sustituida por una nueva central de ciclo combinado), una refinería de petróleo y una empresa química dedicada a la fabricación de la materia prima (caprolactama) de la que se obtiene el nylon-6. Con el objetivo de estudiar y comparar los niveles, la composición y el origen de las partículas PM10, se han seleccionado tres puntos de muestreo. Uno en localidad de Castellón de la Plana y dos en l'Alcora (un punto de situación urbana y otro industrial), en los cuales se han realizado medidas en el periodo de tiempo comprendido entre agosto del año 2005 y diciembre del año 2006.

Human activities such as mining and smelting of lead (Pb) ores and combustion of alkyllead additives in gasoline have resulted in extensive global Pb pollution. Since the late 1960's studies of polar ice and snow have been undertaken to evaluate the extent of anthropogenic Pb emissions in recent times as well as to investigate changes in anthropogenic Pb emissions in the more distant past. The polar ice sheets have been used to investigate Pb pollution as they offer a long-term record of human activity located far from pollution sources and sample aerosol emissions on a hemispheric scale. Lead isotopes have been previously used to identify sources of Pb in polar snow and ice, while new evaluations of Pb isotopic compositions in aerosols and Pb ore bodies allow more thorough evaluations of anthropogenic Pb emissions. Lead isotopic compositions and Pb and Barium (Ba) concentrations have been measured in snow and ice core samples from Law Dome, East Antarctica, to produce a detailed pollution history between 1530 AD and 1989 AD. Such a record has been produced to evaluate changes in anthropogenic Pb emission levels and sources over the past 500 years, to determine when industrial (anthropogenic) activities first began to influence Antarctica and also to investigate natural Pb fluxes to Antarctica. Additional samples were also collected from Law Dome snow and ice cores to respectively investigate seasonal variations in Pb and Ba deposition, and the influence of the 1815 AD volcanic eruption of Tambora, Indonesia. All samples were measured by thermal ionisation mass spectrometry, for which techniques were developed to reliably analyse Pb isotopic compositions in Antarctic samples containing sub-picogram per gram concentrations of Pb.
Particular attention was given to the quantity of Pb added to the samples during the decontamination and sample storage stages of the sample preparation process. These stages, including the use of a stainless steel chisel for the decontamination, contributed ~5.2 pg to the total sample analysed, amounting to a concentration increase of ~13 fg g-1. In comparison, the mass spectrometer ion source contributed typically 89 +/- 19 fg to the blank, however its influence depended upon the amount of Pb available for analysis and so had the greatest impact when small volumes of samples with a very low concentration were analysed. As a consequence of these careful investigations of the Pb blank contributions to the samples, the corrections made to the Pb isotopic ratios and concentrations measured are smaller than previously reported evaluations of Pb in Antarctica by thermal ionisation mass spectrometry. The data indicate that East Antarctica was relatively pristine until -1884 AD, after which the first influence of anthropogenic Pb in Law Dome is observed. "Natural", pre-industrial, background concentrations of Pb and Ba were - 0.4 pg/g and - 1.3 pg/g, respectively, with Pb isotopic compositions within the range 206Pb/207Pb = 1.20 - 1.25 and 208Pb/207Pb = 2.46 - 2.50 and an average rock and soil dust Pb contribution of 8-12%. A major pollution event was observed at Law Dome between 1884 and 1908 AD, elevating the Pb concentration fourfold and changing 206Pb/207Pb ratios in the ice to ~1.12. Based on Pb isotopic systematics and Pb emissions statistics, this was attributed to Pb mined at Broken Hill and smelted at Broken Hill and Port Pirie, Australia.
Anthropogenic Pb inputs to Law Dome were most significant from ~1900 to 1910 and from ~1960 to 1980. During the 20th century, Ba concentrations were consistently higher than "natural" levels. This was attributed to increased dust production, suggesting the influence of climate change and/or changes in land coverage with vegetation. Law Dome ice dated from 1814 AD to 1819 AD was analysed for Pb isotopes and Pb, Ba and Bismuth (Bi) concentrations to investigate the influence of the 1815 AD volcanic eruption of Tambora, Indonesia. The presence of volcanic debris in the core samples was observed from late-1816 AD to 1818 AD as an increase in sulphate concentrations and electrical conductivity of the ice. Barium concentrations were approximately three times higher than background levels from mid-1816 to mid1818, consistent with increased atmospheric loading of rock and soil dust, while enhanced Pb/Ba and Bi/Ba ratios, associated with deposition of volcanic debris, were observed at mid-1814 and from early-1817 to mid-1818. From the results, it appeared likely that Pb emitted from Tambora was removed from the atmosphere within the 1.6 year period required to transport aerosols to Antarctica. Increased Pb and Bi concentrations observed in Law Dome ice ~1818 AD were attributed to either increased heavy metal emissions from Mount Erebus, or increased fluxes of heavy metals to the Antarctic ice sheet resulting from climate and meteorological modifications following the Tambora eruption.
A non-continuous series of Law Dome snow core samples dating from 1980 to 9185 AD were analysed to investigate seasonal variations in the deposition of Pb and Ba. It was found that Pb and Ba at Law Dome do exhibit seasonal variations in deposition, with higher concentrations of Pb and Ba usually observed during Summer and lower concentrations of Pb and Ba usually observed during the Autumn and Spring seasons. At Law Dome, broad patterns of seasonal Pb and Ba deposition are evident however these appear to be punctuated by short-term deposition events or may even be composed of a continuum of short-term deposition events. This variability suggests that complex meteorological systems are responsible for the transport of Pb and Ba to Law Dome, and probably Antarctica in general.

Etude des emissions naturelles de carbone particulaire et evaluation des perturbations induites par les activites humaines sur le cycle atmospherique du carbone. Travail s'appuyant sur des mesures de concentration et de granulometrie d'aerosol preleve au cours de nombreuses campagnes en milieu continental tempere et tropical ainsi qu'en zone oceanique des deux hemispheres. L'origine et le transport a grande echelle des aerosols sont determines par des mesures de composition isotopique (**(13)c/**(12)c) au spectrometre de masse

Stratospheric sulfate aerosols (SSA) play an important part in regulating the climate of the earth and in the maintenance of important stratospheric species, including stratospheric ozone. The sources of stratospheric sulfate aerosol sulfur remain an unresolved issue because of uncertainties in the global sulfur budget and model limitations. The origins of SSA particles should be reflected in their isotopic composition. In this thesis project, the sulfur isotopic fractionation factors of processes that produce stratospheric sulfate aerosols (SSA) were quantified using a variety of theoretical and experimental techniques. RRKM (unimolecular dissociation) theory was applied to compute the isotopic fractionation of the homogeneous oxidation of SO2 via OH radicals. The overall isotopic enrichment associated with the total OCS loss pathways in the stratosphere was determined by analyzing high resolution FT-IR data from balloon flights. The isotopic fractionation of the photolytic decomposition of OCS was estimated by measuring the absorption spectra of OCS sulfur isotopologues. We also measured the isotopic composition of stratospheric aerosols sampled during the period 1973-1974, in the course of the Department of Energy?s AIRSTREAM campaign. Combining our results with literature values of the sulfur isotopic composition of SSA precursors, we modeled the steady-state isotopic composition of sulfur compounds in the atmosphere using the JPL/Caltech 1-D chemical transport model. Our data supports the view that OCS and SO2 are both important in the maintenance of the background stratospheric sulfate aerosol layer.

The sources of ambient organic particulate matter in urban areas are investigated through a program of emission source measurements, atmospheric measurements, and mathematical modeling of source/receptor relationships. A dilution sampler intended to collect fine organic aerosol from combustion sources is designed to simulate atmospheric cooling and dilution processes, so that organic vapors which condense under ambient conditions will be collected as particulate matter. This system is used to measure the emissions from a boiler burning distillate oil, a home fireplace, catalyst and noncatalyst automobiles, heavy-duty diesel trucks, natural gas home appliances, and meat cooking operations. Alternate techniques are used to sample the particulate matter emitted from cigarette smoking, a roofing tar pot, paved road dust, brake lining wear, tire wear, and vegetative detritus. The bulk chemical characteristics of the fine aerosol fraction are presented for each source. Over half of the fine aerosol mass emitted from automobiles, wood burning, meat cooking, home appliances, cigarettes, and tar pots is shown to consist of organic compounds. The organic material collected from these sources is analyzed using high-resolution gas chromatography. Using a simple analytical protocol, a quantitative, 50-parameter characterization of the elutable fine organic aerosol emitted from each source type is obtained, which proves to be a unique fingerprint that can be used to distinguish most sources from each other. A mathematical model is used to predict the characteristics of fine ambient organic aerosol in the Los Angeles area that would prevail if the primary organic emissions are transported without chemical reaction. The model is found to track the seasonal variations observed in the ambient aerosol at the three sites studied. Emissions from vehicles and fireplaces are identified as significant sources of solvent-extractable organic aerosol. Differences between the model predictions and ambient concentrations that could be due to atmospheric chemical reaction are discussed. An upper limit on the amount of secondary organic aerosol present is estimated based on the difference between the acidic organic aerosol present in ambient samples versus that due to primary emissions as computed by the model. Finally, several hypotheses concerning the origin of the acidic organic aerosol are proposed.

碩士
國立中央大學
環境工程研究所
97
The tremendous amounts of aerosols and gas pollutants produced in Indo China will affect the downwind region as they are transported in a long distance. Taiwan is one of the best places to observe these transported pollutants as it is located in the downwind region. To circumbent the interference from ground level pollution, this study observed atmospheric aerosols at Mt. Lulin (2,862 m above sea level) from July 2007 to April 2008. The goal is to resolve the differences of aerosol property between biomass burning (BB) and non-biomass burning (NBB) periods. The PM2.5 level is three-fold during BB period as compared to that of NBB period. The PM2.5 ammonium ion, sulfate, and nitrate levels are 1.50 µg m-3, 4.06 µg m-3, and 0.50 µg m-3, respectively. Notably, the PM2.5 potassium ion as one of the markers for BB was four-fold as high as that during NBB period. As for the levels of the resolved carbonaceous fractions, organic carbons (OC) were increased significantly, while only EC1-OP was increased for elemental carbon (EC). Moreover, the mean values of water-soluble OC, levoglucosan, and low molecular-weight diacids during BB period were 3.2, 3, and 4.5 times, respecticely, in contrast to those during NBB period. Trajectory analysis for the air masses during observation period shows that the levels of aerosol components were the lowest for oceanic origin. It also shows that PM10-2.5 and calcium ion from China continent were apparently higher than those from other transport paths probably due to the influence of Asian dust. For the air masses from BB source region via southern China, PM2.5, potassion ion, oxalic acid, and levoglucosan were all higher during BB period than that of NBB period. For the aerosol morphology during BB period, the analysis of scanning electron microscopy reveals that rectangular crystal type is around 70-80% in the number of the observed aerosol particles followed by tar ball type and grape chain aggregrate takes the least. Different size cut samplers were adopted at Mt. Lulin to collect aerosols when in the uprising convective cloud, little difference was found for PM1 and PM2.5 aerosol components; however, a difference was exist for PM1 and TSP. Among aerosol components, the scavenging ratio was highest at 0.41 for nitrate followed by ammonium ion and sulfate. The scavenging ratio for OC and EC were 0.20 and 0.22, respectively. During cloud affecting period, the levels of PM2.5 ammonium ion, sulfate, and nitrate were significantly increased, which indicates anthropogenic pollutants were entrained in the cloud.