Les Composés Organiques Volatils (COV), émis dans l'atmosphère sous différentes formes par les activités industrielles, sont considérés comme des polluants principaux de l'air. Pour le traitement des forts débits de gaz faiblement concentrés en COV, caractéristiques des principales sources de COV industriels, il n'existe que très peu de procédés adaptés et efficaces d'où le plasma non thermique. Sa faible consommation d'énergie et sa grande compacité font du traitement par plasma non-thermique un candidat prometteur. Ma thèse consiste à élaborer et étudier un dispositif de traitement des COV basé sur l'utilisation de décharges à barrière diélectrique de surface, décharges ayant la caractéristique de produire un vent électrique dirigé. Pour ce faire, nous avons conçu et optimisé une pompe plasma chimiquement active, composée d'un assemblage de cellules à surfaces actives, capable d'aspirer et de traiter simultanément de l'air pollué en COV. Il a fallu d'abord travailler sur l'optimisation paramétrique : électrique, géométrique et matériaux, d'une surface active élémentaire. Puis concevoir un canal actif constitué de deux surfaces actives optimales placées en vis-à-vis, pour finalement aboutir à la construction d'une pompe plasma prototype ayant un débit de pompage de 10 Nm3/h. Cette pompe originale par sa capacité de traitement chimique, constitue le prototype d'étude physique et chimique de cette thèse. Elle a permis d'effectuer des essais d'élimination de 5 COV différents injectés dans l'air : acétone, méthyl-éthyle cétone, butyraldéhyde, méthyl-valérate, méthyl-butyrate et d'en évaluer les taux d'abattement respectifs, mais aussi, d'identifier à l'aide de la chromatographie en phase gazeuse couplée à la spectrométrie de masse, les principaux sous-produits de la dégradation. / The Volatile Organic Compounds (VOC) emitted in the atmosphere by various forms is considered as principal atmospheric pollutant. In order to treat a high flow of gaz with a low concentration, few efficient methods exist like the non-thermal plasma. Its low power consumption and compactness make the non-thermal plasma treatment a promising candidate. My thesis deals with the development and study of a VOC treatment device based on the surface dielectric barrier discharges which have the characteristic of producing an oriented electric wind. To do this, we have designed and optimized a chemically active plasma pump, composed of an assembly of active surfaces, capable of drawing and treating simultaneously the air polluted in VOC. At first, we had to work on the optimization of the following parameters: electrical, geometric and material of an elementary active surface. And then conceive an active channel consisting of two optimal active surfaces disposed in a mirror effect, eventually leading to the construction of a prototype plasma pump having a flow rate approximately equal to 10 Nm3/h. This original pump by its capacity of chemical treatment consists on the physical and chemical prototype of the thesis. It allowed testing the conversion of 5 different VOCs injected into air which are: ketone, methyl ethyl ketone, butyraldehyde, methyl penatanoate, methyl butyrate and evaluate the respective abatement rates, but also identifying the main by-products of degradation, using the gas chromatography coupled to the mass spectrometry.

In this thesis the oxidation of monoterpenes by O3 and NO2 and factors that influenced the oxidation were studied. In the environment both ozone (O3) and nitrogen dioxide (NO2) are present as oxidising gases, which causes sampling artefacts when using Tenax TA as an adsorbent to sample organic compounds in the air. A scrubber was developed to remove O3 and NO2 prior to the sampling tube, and artefacts during sampling were minimised when using the scrubber. The main organic compounds sampled in this thesis were two monoterpenes, alfa-pinene and delta-3-carene, due to their presence in both indoor and outdoor air. The recovery of the monoterpenes through the scrubber varied between 75-97% at relative humidities of 15-75%. The reactions of alfa-pinene and delta-3-carene with O 3, NO2 and nitric oxide (NO) at different relative humidities (RHs) and reaction times were studied in a dark reaction chamber. The experiments were planned and performed according to an experimental design were the factors influencing the reaction (O3, NO2, NO, RH and reaction times) were varied between high and low levels. In the experiments up to 13% of the monoterpenes reacted when O3, NO2, and reaction time were at high levels, and NO, and RH were at low levels. In the evaluation eight and seven factors (including both single and interaction factors) were found to influence the amount of alfa-pinene and delta-3-carene reacted, respectively. The three most influencing factors for both of the monoterpenes were the O 3 level, the reaction time, and the RH. Increased O3 level and reaction time increased the amount of monoterpene reacted, and increased RH decreased the amount reacted. A theoretical model of the reactions occurring in the reaction chamber was created. The amount of monoterpene reacted at different initial settings of O3, NO2, and NO were calculated, as well as the influence of different reaction pathways, and the concentrations of O3 and NO2, and NO at specific reaction times. The results of the theoretical model were that the reactivity of the gas mixture towards alfa-pinene and delta-3-carene was underestimated. But, the calculated concentrations of O3, NO2, and NO in the theoretical model were found to correspond to a high degree with experimental results performed under similar conditions. The possible associations between organic compounds in indoor air, building variables and the presence of sick building syndrome were studied using principal component analysis. The most complex model was able to separate 71% of the “sick” buildings from the “healthy” buildings. The most important variables that separated the “sick” buildings from the “healthy” buildings were a more frequent occurrence or a higher concentration of compounds with shorter retention times in the “sick” buildings. The outcome of this thesis could be summarised as follows; - - - -

<p>In this thesis the oxidation of monoterpenes by O3 and NO2 and factors that influenced the oxidation were studied. In the environment both ozone (O3) and nitrogen dioxide (NO2) are present as oxidising gases, which causes sampling artefacts when using Tenax TA as an adsorbent to sample organic compounds in the air. A scrubber was developed to remove O3 and NO2 prior to the sampling tube, and artefacts during sampling were minimised when using the scrubber. The main organic compounds sampled in this thesis were two monoterpenes, alfa-pinene and delta-3-carene, due to their presence in both indoor and outdoor air. The recovery of the monoterpenes through the scrubber varied between 75-97% at relative humidities of 15-75%.</p><p>The reactions of alfa-pinene and delta-3-carene with O 3, NO2 and nitric oxide (NO) at different relative humidities (RHs) and reaction times were studied in a dark reaction chamber. The experiments were planned and performed according to an experimental design were the factors influencing the reaction (O3, NO2, NO, RH and reaction times) were varied between high and low levels. In the experiments up to 13% of the monoterpenes reacted when O3, NO2, and reaction time were at high levels, and NO, and RH were at low levels. In the evaluation eight and seven factors (including both single and interaction factors) were found to influence the amount of alfa-pinene and delta-3-carene reacted, respectively. The three most influencing factors for both of the monoterpenes were the O 3 level, the reaction time, and the RH. Increased O3 level and reaction time increased the amount of monoterpene reacted, and increased RH decreased the amount reacted.</p><p>A theoretical model of the reactions occurring in the reaction chamber was created. The amount of monoterpene reacted at different initial settings of O3, NO2, and NO were calculated, as well as the influence of different reaction pathways, and the concentrations of O3 and NO2, and NO at specific reaction times. The results of the theoretical model were that the reactivity of the gas mixture towards alfa-pinene and delta-3-carene was underestimated. But, the calculated concentrations of O3, NO2, and NO in the theoretical model were found to correspond to a high degree with experimental results performed under similar conditions. The possible associations between organic compounds in indoor air, building variables and the presence of sick building syndrome were studied using principal component analysis. The most complex model was able to separate 71% of the “sick” buildings from the “healthy” buildings. The most important variables that separated the “sick” buildings from the “healthy” buildings were a more frequent occurrence or a higher concentration of compounds with shorter retention times in the “sick” buildings.</p><p>The outcome of this thesis could be summarised as follows;</p><p>-</p><p>-</p><p>-</p><p>-</p>

Hippocrates predicted many years ago that breath could tell something related with our health. On his treaties, he indicated that when the body starts moving after sleeping, and breathe with more frequency, something hot and acid is expelled with air. It is possible to predict a disease from breath, but it has not been until recent years that last developments in breath analysis has allowed to detect compounds precisely and to associate the presence of these compounds to certain diseases. The use of breath analysis in clinical diagnosis and exposure to contaminants presents great advantages as this is a non-invasive technique, compared with other techniques such as blood or urine analyses. Two new instrumental methodologies have been developed in the present thesis, which are based on adsorbent micro-traps, specifically designed for the analysis of volatile compounds in breath and environmental samples. These equipments are versatile and low cost, compared to other commercially available instrumentations. One of the methodologies developed has been designed for the analysis volatile compounds in breath samples, showing efficiency and resolutions unknown up to know. It has allowed detecting exposure to volatile contaminants in a range of concentrations that the current techniques cannot achieve. The second equipment has been developed for the analysis of the same contaminants in other biological matrixes, in this case blood. It has been used to assess the mechanism followed by the inhaled compounds when entering the human body. These new methodologies were evaluated in different exposure studies. 2,5-dimethylfurean was detected with a high sensitivity and allowed to determine the smoking habits of a wide group of individuals, also 48 hours after smoking. The levels of contamination due environmental tobacco smoke were also evaluated in different environments. The high sensitivity of the developed techniques allowed us to demonstrate the contamination of passive smokers by environmental tobacco smoke (ETS) after few hours of being in contact with. Breath levels of the smoking biomarker after few hours in contact with ETS where at the same level that those found in smokers who smoke few cigarettes per day / Que l’alè ens deia alguna cosa de la nostra salut ja ho va intuir Hipòcrates. Al Tractat Mèdic hi va escriure: “Així, doncs, quan el cos es posa en moviment després de dormir i respira amb més freqüència, quelcom calent i àcid és expulsat amb l’aire. D’això en venen malalties si hom no pren precaucions.” Sí, de l’olor de l’alè s’intuïen malalties però no ha estat fins als darrers anys, que els nous avanços en les tècniques d’anàlisi no han proporcionat els mecanismes adients per detectar els compostos de forma inequívoca i poder associar la seva presència a l’alè a determinades malalties. Tant des d’un punt de vista mèdic com d’exposició a contaminants, el principal avantatge de poder disposar d’una anàlisi d’alè consisteix en la metodologia diagnòstica, que no és invasiva i, per tant, no presenta els inconvenients associats a altres tècniques convencionals, com son l’anàlisi de sang i d’orina. En aquesta tesi s’han desenvolupat dos noves metodologies instrumentals, basades en micro-trampes d’adsorció, especialment dissenyades per a l’anàlisi de compostos volàtils en mostres gasoses, principalment mostres ambientals i mostres d’alè humà. Aquests nous equipaments es caracteritzen per la seva versatilitat i molt baix cost, si es comparen amb els equips comercials actuals. Un dels prototips s’ha dissenyat per a l’anàlisi de mostres d’alè, mostrant una eficàcia i resolució desconeguda fins ara, el que ha permès detectar l’exposició a contaminants volàtils a uns nivells que les tecnologies actuals no permeten assolir. El segon equipament ha estat desenvolupat per permetre analitzar els mateixos contaminants en matrius biològiques, en aquest cas sang, i poder determinar de quina manera i en quin percentatge els compostos que inhalem per exposició arriben a entrar en el cos humà. Aquestes noves metodologies s’han avaluat en diferents estudis d’exposició. S’ha pogut detectar un compost, el 2,5-dimetilfuran, amb una elevada sensibilitat per a la detecció de l’hàbit fumador de les persones, inclús després de més de 48 h d’haver fumat una cigarreta. També s’han estudiat els nivells de contaminació pel fum ambiental del tabac que tenen lloc en diferents ambients (locals de fumadors i no-fumadors). L’elevada sensibilitat de les tècniques desenvolupades ha permès demostrar “in-situ” per primera vegada que els fumadors passius només requereixen unes poques hores de contacte en un ambient contaminat pel fum del tabac per presentar nivells de contaminació a l’alè similars als dels fumadors de poques cigarretes al dia

Along with industrial and economic growth there is a persistent risk of permanently increasing air pollution. Air pollution has especially grown in the second half of the 20th century due to intense development of energy, industry and transport sectors. These pollution sources still remain the largest air polluters. Solvents, paints, glues, ink and other substances, emitting volatile organic compounds to air are used in such industries like reel, metal and wood coating, covering with glue sticks, footwear production, production of pharmaceutical products, printing, dry (chemical) surface cleaning etc. Emissions of volatile organic compounds make harm both to people and environment as well as damage the ozone layer. Volatile organic compounds also affect smog formation and green house effect. In the paper it is hypothesised that after implementation of EU legislation, observing the given emission limit values, improving technologies and implementing new treatment technologies, applying the measures to reduce pollution with volatile organic compounds and replacing the materials, emitting volatile organic compounds, with less polluting ones or those without pollution, air emission of volatile organic compounds will reduce dramatically. This master’s paper reviews the measures and ways to manage pollution with volatile organic compounds (VOC): directives and their requirements, transferred to the national laws of the member states, addressed to solve the VOC pollution problem... [to full text]