Dissertations / Theses on the topic 'Volatile Carbonyl Compounds'

Les biocarburants présentent une alternative prometteuse à l'utilisation de carburants fossiles. Cependant, l'augmentation de la quantité de biocarburants introduite dans les carburants nécessite de connaître leur impact sur les émissions de polluants. Le travail réalisé lors de cette thèse peut être décrit en deux parties : La première traite de l'évaluation des émissions de polluants réglementés et non réglementés émis par la combustion de biocarburants dans un moteur diesel. Différents biocarburants ont été testés : des esters méthyliques d'huile de soja et de colza, des esters éthyliques d'huile usagée et un carburant de référence exempt de tout biocarburant. Les résultats montrent que la nature des biocarburants ainsi que leur teneur ont un impact sur les polluants émis. Par exemple, une diminution de la taille des particules émises a été observée avec l'utilisation des esters méthyliques d'huile de soja. Le deuxième objectif de cette thèse concerne le piégeage des polluants Diesel, notamment des composés organiques volatils par des zéolithes. Plusieurs zéolithes ont été synthétisées puis caractérisées. Des tests d'adsorption par thermogravimétrie ont ensuite été réalisés au laboratoire avec différentes molécules sondes représentatives des polluants émis par les moteurs Diesel (le n-hexane, le p-xylène et l'acétone). Certaines zéolithes comme les zéolithes faujasite présentent des capacités d'adsorption intéressantes. Toutefois, la plupart des résultats montrent une diminution de la capacité d'adsorption avec l'augmentation de la température. Ces zéolithes ont ensuite été placées en sortie d'échappement d'un moteur diesel afin d'étudier leur capacité d'adsorption.

Les composes carbonyles et BTEX (benzène, toluène, éthylbenzène et xylène) sont deux groupes importants de composés organiques volatils (COV) présents dans l'atmosphère. Ils ont une contribution significative à la formation d'oxydants tels que l'ozone, PAN et d'autres photo-oxydants dans la troposphère. En outre, ils ont des effets néfastes sur la santé humaine. Dans ce travail, les concentrations atmosphériques de carbonyles et d’hydrocarbures aromatiques ont été mesurées et quantifiées en utilisant des techniques HPLC et GC-MS sur un site de mesure semi-urbain à Orléans (ICARE, France), de juin 2010 à août 2011. D’autres mesures ont été conduites à Pékin (CAS-RCEES, Chine) du 6 au 28 Juin 2013 en utilisant les mêmes techniques expérimentales. Les résultats obtenus dans ces deux sites sont présentés, comparés et discutés
Carbonyls and BTEX (benzene, toluene, ethyl-benzene and xylene) are two important groups of Volatile Organic Compounds (VOCs) present in the atmosphere. They have a significant contribution to the formation of oxidants such as ozone, PAN and other photooxidants in the troposphere. In addition, they have adverse effects on human health. In this work, atmospheric concentrations of carbonyls and aromatic hydrocarbons were measured and quantified using GC-MS and HPLC techniques at a semi-urban site in Orleans (ICARE, France), from June 2010 to August 2011. Urban ambient air sampling was also performed in 6-28th June 2013 in Beijing (RCEES-CAS, China). It has been conducted in order to compare the measured concentrations of the investigated species in two different sites using the same analytical techniques. All results are presented and discussed

A quantificação de 11 compostos carbonílicos (formaldeído, acetaldeído, acetona, acroleína, propionaldeído, crotonaldeído, butiraldeído, benzaldeído, isovaleraldeído, valeraldeído e 2,5-dimetilbenzaldeído) e a identificação de outros 43 compostos orgânicos voláteis (alcanos, alcenos, aromáticos, halogenados e nitrogenados) foram feitas em 9 ambientes diferentes de trabalho localizados em áreas internas do Hospital Universitário, USP, São Paulo. Dentre os compostos carbonílicos, os mais abundantes em ordem decrescente foram formaldeído, acetona, acetaldeído e acroleína. As maiores razões de mistura de formaldeído foram observadas nas salas de Macroscopia (169,9 e 90,2 ppbv) e Técnicas Histológicas (11,7 e 58,7 ppbv), em decorrência da atividade desenvolvida nos locais. Na sala de Macroscopia, os níveis de formaldeído encontrados foram acima do limite (100 ppbv) estabelecido por órgãos internacionais que controlam a qualidade do ar em ambientes internos não industriais. As razões de mistura entre o ambiente interno e o ambiente externo, razões I/E, permitiram indicar a predominância dos compostos carbonílicos nos ambientes internos. A acroleína foi encontrada na faixa de 6,4 a 9,3 ppbv nos ambientes internos estudados. Na área externa, entretanto, foram encontrados valores similares (6,4 e 6,8 ppbv) aos dos ambientes internos obtendo razões I/E próximas de 1. Os compostos podem ter sido emitidos por materiais de construção e acabamento, fumaça do tabaco, adesivos, via metabolismo microbiano e bacteriano ou podem ter sido transportados por correntes de ar do ambiente externo para o ambiente interno
The quantification of 11 carbonyl compounds (formaldehyde, acetaldehyde, acrolein, acetone, propionaldehyde, crotonaldehyde, butiraldehyde, benzaldehyde, isovaleraldehyde, valeraldehyde and 2,5-dimethylbenzaldehyde) and the identification of another 43 volatile organic compounds (alkanes, alkenes, aromatic, halogenated and nitrogenated compounds) have been done with samples of 9 different indoor places inside the University Hospital at USP in São Paulo. Among the carbonyl compounds, there where found higher quantities of formaldehyde, acetone, acetaldehyde and acrolein in this order. The highest ratios of formaldehyde mixture have been observed at the Macroscopic room (169.88 and 90.2 ppbv) and Histological Techniques (11.7 and 58.7 ppbv), due to the routine activities of these places. At the Macroscopy room, the level of formaldehyde identified (100 ppbv) was above the international limits established to non-industrial internal places. The ratios of the mixture of indoor and outdoor places, I/O, indicate the biggest presence of carbonyl compounds in internal places. Acrolein has been identified (6.4 to 9.3 ppbv) at indoor places. At the external area, there where found similar values (6,4 to 6,8 ppbv), and the ratio I/O obtained is near to 1. The origin of these compounds is possibly construction materials, smoke of cigarettes, adhesives, metabolism of microorganisms or they may have come from the outdoor to the indoor

L’activité phytoplanctonique est à l’origine de la production dans l’océan de composés volatils, qui, une fois émis dans l’atmosphère, ont un impact sur sa capacité oxydante, la formation d’aérosols et la régulation du climat. Les émissions océaniques de la plupart de ces composés sont néanmoins mal connues en raison d’un faible nombre d’observations in situ et d’un manque de connaissance dans les processus océaniques en jeu. Dans un premier temps, je me suis intéressée aux cycles océaniques du monoxyde de carbone (CO) et de l’isoprène (C5H8). Afin de ré-évaluer leurs émissions vers l’atmosphère, les processus de production et de consommation de ces gaz dans la colonne d’eau ont été intégrés au modèle 3-D de circulation océanique et de biogéochimie marine NEMO-PISCES. En parallèle, des compilations de concentrations océaniques mesurées in situ et de résultats de laboratoire ont été réalisées à partir de la littérature afin de mieux contraindre ces processus océaniques. J'ai obtenu les premières spatialisations des émissions de CO et isoprène basées sur un modèle 3-D de l'océan et ne faisant pas appel à des données satellites pour le calcul des concentrations. Pour le CO, les émissions globales sont estimées à 4,0 Tg C an-1, avec une dynamique spatiale qui reflète principalement sa source photochimique. Cette dynamique est très différente de celle produite dans les années 80, qui était la seule disponible pour la communauté de chimistes de l’atmosphère. Pour l’isoprène, j'ai montré l’importance de la température de l’eau dans la régulation de sa production phytoplanctonique. Les émissions globales sont estimées à 0,66 Tg C an-1, avec une dynamique spatiale qui reflète cette source. Pour les deux composés, j’ai également montré l’importance des effets de la circulation et du mélange océaniques dans la détermination des concentrations de surface et donc des émissions vers l’atmosphère. Dans un second temps, je me suis intéressée aux réponses des émissions océaniques de CO, isoprène et sulfure de diméthyle (DMS) au changement climatique. Celui-ci conduit à une augmentation des émissions des 3 gaz (+9,4, +4,2 et +6,5% pour le CO, l’isoprène et le DMS en 2100 pour un scénario à fortes émissions de gaz à effet de serre). Les émissions ont tendance à augmenter aux hautes latitudes et à diminuer aux basses latitudes. Les changements globaux sont principalement contrôlés par les changements de température de l'eau, alors que les changements dans la distribution spatiale sont contrôlés par une redistribution de la production phytoplanctonique. Même si les incertitudes sur la modélisation de ces cycles est encore importante, ce travail devrait permettre à terme d’intégrer ces cycles dans un modèle du système terre, couplant biogéochimie marine et chimie atmosphérique, afin de mieux quantifier le rôle potentiel de ces interactions sur l’évolution de la chimie atmosphérique et du climat
Phytoplankton activity is responsible for the oceanic production of volatile compounds which, once released into the atmosphere, have an impact on its oxidative capacity, on aerosol formation and on climate evolution. The oceanic emissions of most of these compounds are, however, poorly known because of a low number of in situ observations and a lack of knowledge in the oceanic processes involved. In a first step, I studied the oceanic cycles of carbon monoxide (CO) and isoprene (C5H8). In order to re-evaluate their emissions to the atmosphere, the sources and sinks of these gases in the water column have been embedded into the 3-D ocean circulation and marine biogeochemistry model NEMO-PISCES. In parallel, I compiled in situ measured oceanic concentrations and laboratory results from the literature to better constrain these oceanic processes. I produced the first spatialization of CO and isoprene emissions based on a 3-D ocean model and not relying on satellite data for the calculation of concentrations. For CO, global emissions are estimated to 4.0 Tg C yr-1, with a spatial dynamic reflecting its photochemical source. This dynamic is very different from the one produced in the 80s, which was the only one available to the atmospheric chemistry community. For isoprene, I showed the importance of water temperature in regulating the phytoplankton production. Global emissions are estimated to 0.66 Tg C yr-1, with a spatial dynamic reflecting this source. For both compounds, I also showed the importance of ocean circulation and mixing in determining surface concentrations and therefore emissions to the atmosphere. In a second step, I studied the responses of oceanic emissions of CO, isoprene and dimethyl sulfide (DMS) to climate change. This leads to an increase in the emissions of the 3 gases (+9.4, +4.2 and +6.5% for CO, isoprene and DMS in 2100 for a scenario with high emissions of greenhouse gases). Emissions tend to increase at high latitudes and decrease at lower latitudes. Global changes are mainly controlled by changes in water temperature, while changes in spatial distribution are controlled by a redistribution of phytoplankton production. Even if the uncertainties in modeling these cycles are still important, this work should allow integrating these cycles into an Earth System model coupling marine biogeochemistry and atmospheric chemistry, in order to better quantify the potential role of these interactions on the evolution of atmospheric chemistry and climate

Les composés organiques carbonylés et les BTEX (Benzène, Toluène, Éthylbenzène et Xylènes) représentent une classe importante de composés organiques volatils dans l’atmosphère. Ils sont émis par des sources anthropogénique et biogéniques. Leur dégradation atmosphérique conduit à la formation d’ozone, de phooxidants et d’aérosols organiques affectant ainsi la qualité de l’air aux échelles locales et régionales ainsi que la santé humaine. Il est donc important de mesurer leurs concentrations et évaluer leur devenir atmosphérique. Dans la présente thèse, nous avons conduit une étude systématique qui a permis de mesurer les concentrations de ces composés et identifier leurs sources à Pékin (Juillet 2008-Août 2010) et évaluer l’importance des caractéristiques météo. Nous avons aussi mené des études sur la dégradation atmosphérique de trois formates (isoproyle, isobutyle et n-propyle) en utilisant la chambre de simulation atmosphérique d’ICARE (CNRS, Orléans)
Carbonyls and BTEX (Benzene, Toluene, Ethylbenzene, and Xylenes) represent an important class of VOCs (volatile organic compounds) in the atmosphere. They are emitted into the atmosphere through anthropogenic and biogenic sources. Their atmospheric degradation leads to the formation of ozone, photooxidants and organic aerosols affecting the air quality at the local and regional scales and human health. It is, hence, of importance to measure their atmospheric concentrations and investigate their fate. In the present thesis, we have conducted a systematic measurement study of carbonyls and BTEX in Beijing during the period of Jul 2008-Aug 2010 in order to evaluate their ambient levels, possible sources and the influence of characteristic weather conditions. In a separate work, we performed a series of experimental studies on the OH-initiated oxidation of isopropyl formate, isobutyl formate, and n-propyl isobutyrate using the ICARE-CNRS (Orleans) simulation chamber from which we derived the product yields. The data obtained are presented and discussed

Les composés organiques volatils oxygénés (COVOs) sont des espèces chimiques importantes de l’atmosphère. Ils incluent, par exemple, les alcools aliphatiques, les aldéhydes, les cétones et les acides organiques. Dans la troposphère libre, l’abondance des COVOs est plus importante que celle des hydrocarbures non méthaniques et leur réactivité globale avec OH est comparable avec celle du méthane. En revanche le méthane est présent à une concentration plus élevée. La dégradation des COVOs dans l’atmosphère s’effectue soit par la réaction avec le radical OH, soit par photolyse. La dégradation des COVOs produit des radicaux libres qui vont influencer la capacité oxydante de l’atmosphère, les concentrations en oxydes d’azotes, en radical OH et en ozone troposphérique. L’ozone est le troisième plus important gaz à effet de serre dans l’atmosphère et est l’un des composants toxiques principaux des pollutions urbaines et intervient donc dans des problèmes environnementaux graves comme le réchauffement climatique et la dégradation de la qualité de l’air. L’objectif de ce travail est de contribuer à la compréhension du comportement atmosphérique de quelques COVOs en mesurant leurs paramètres cinétiques et photochimiques apportant des donnés afin de permettre la réalisation de modélisations informatiques et l’amélioration de la connaissance des mécanismes chimiques ayant lieu dans l’atmosphère
Oxygenated volatile organic compounds (OVOCs) are important constituents of the atmosphere. They include, e.g., aliphatic alcohols, aldehydes, ketones, and organic acids. In the free troposphere, the abundance of OVOCs is higher than that of the non-methane hydrocarbons and their overall reactivity with OH is comparable with that of methane, in contrast that methane is present in much higher concentration. Degradation of OVOCs in the atmosphere takes place via the reaction with OH radicals and, in the case of photochemically active molecules, via photolysis. Free radicals are formed in the photooxidative degradations of the oxygen containing organics which basically determine the oxidative capacity of the atmosphere, the transformation of nitrogen oxides and the concentration of OH radicals and tropospheric ozone. Ozone is the third most important greenhouse gas in the atmosphere, it is one of the toxic components of urban smog and so it is related to such grave environmental problems as global warming and the quality of air. The aim of this work is to contribute to the understanding of the atmospheric behaviour of a few OVOCs by measuring their kinetic and photochemical parameters. One of the major goals of a laboratory basic research in atmospheric chemistry is to provide kinetic and photochemical data for computer modelling and to deduce atmospheric transformation mechanisms in the case of some important chemicals

Ce manuscrit s’intéresse à une filière globale et durable de dépollution des eaux souterraines. Le polluant cible, le tétrachloroéthylène, est un composé organique volatil. La première étape de cette filière est la séparation du contaminant de l’eau. Elle a été réalisée par adsorption sur charbons actifs dans une colonne en lit fixe. Les résultats obtenus en laboratoire sur les capacités et les cinétiques d’adsorption ont permis de montrer l’efficacité de ce procédé. Un modèle issu de ces expériences a représenté correctement des conditions opératoires variées correspondant à celles utilisées dans l’industrie. Ce modèle a été validé par un pilote préindustriel installé sur site et fonctionnant en conditions réelles. La gestion des charbons actifs chargés en polluant a été étudiée. La régénération thermique a été privilégiée. Cette opération présente l’intérêt de rétablir les capacités d’adsorption des carbones activés et de récupérer les polluants en phase liquide. Bien que préférable à la production d’adsorbants, elle pourrait encore être plus durable et compétitive économiquement en effectuant le traitement thermique par voie solaire. Il a été montré que le taux de régénération est le même pour les régénérations solaire et classique. Il est donc possible, dans le cas du tétrachloroéthylène, de remplacer une source d’énergie fossile par le soleil. La solution de distillat obtenue lors de la régénération peut être minéralisée par photocatalyse hétérogène. Cette opération a été réalisée en laboratoire avec une lampe reproduisant le spectre solaire. La faisabilité de la photocatalyse solaire sur le résidu issu de cette filière de dépollution a ainsi été montrée
This manuscript focuses on a comprehensive and durable treatment of polluted groundwater. The target contaminant, tetrachlorethylene, is a volatile organic compound. The first step in the treatment is the separation of contaminants. It was carried out by adsorption on activated carbons in a fixed bed column. The results obtained in the laboratory on the adsorption capacity and kinetics have shown the efficiency of this process. A mathematic model represented properly the various operating conditions corresponding to those used in the industry. This model has been validated by a pre-industrial pilot installed onsite and operating in real conditions. Management of spent activated carbons was studied. The thermal regeneration was chosen because it has the interest to restore the adsorption capacity of adsorbents and to collect the pollutants in a liquid phase. Although preferable to the production of activated carbons, it could still be economically more competitive and more sustainable by performing the heat treatment by solar means. It has been shown that the regeneration rate is the same for the solar and classical regenerations. It is therefore possible, in the case of tetrachlorethylene, to replace a fossil energy source by the sun.The distillate solution obtained during the regeneration can be mineralized by heterogeneous photocatalysis. This operation was carried out in the laboratory with a lamp reproducing the solar spectrum. The feasibility of solar photocatalysis on the final residue of the water treatment has been shown

La combustion de la biomasse et en particulier du bois constitue une alternative intéressante à l'utilisation des combustibles fossiles pour l'approvisionnement en énergie. Elle présente l'avantage de pouvoir être renouvelable sans contribuer à une émission supplémentaire de CO₂. Cependant, il est connu que les appareils de chauffage utilisant la biomasse comme combustible peuvent générer certains polluants gazeux dont notamment les Composés Organiques Volatils (COV) et le monoxyde de carbone (CO). Le post-traitement catalytique se révèle comme une des technologies les plus prometteuses pour limiter ces émissions de polluants. Ce projet vise donc à développer des matériaux catalytiques actifs, sélectifs en dioxyde de carbone et stables, assurant une décomposition complète du mélange de COV et de CO. Les catalyseurs à base de métaux nobles, étant reconnus pour leur bonne activité pour ce type de réaction d'oxydation, engendrent cependant un coût important pour le développement d'un tel procédé. L'objectif de nos travaux sera donc basé sur la synthèse et le développement de nouveaux matériaux catalytiques peu onéreux à base d'oxydes de métaux de transition qui seront utilisés comme alternatifs aux catalyseurs à base de métaux nobles. Afin d'obtenir des oxydes performants, la synthèse des matériaux en utilisant la voie hydrotalcite a été choisie. Nous avons montré l'effet bénéfique de l'ajout du cérium dans les oxydes MgAl-O et CuAl-O vis-à-vis de l'oxydation du toluène et/ou du CO. Une relation entre la réductibilité et l'activité de ces solides pour ces réactions a été observée. Pour les catalyseurs MgAlCe-O, aucun effet sur la conversion du toluène n'a été observé, cependant un effet significatif sur la conversion du CO en présence de toluène a été mis en évidence. Ainsi, un oxyde du type CuAlCe-O s'est avéré actif et stable pour la destruction de mélanges de COV et de CO. De plus, l'intérêt d'utiliser la voie hydrotalcite pour synthétiser ces oxydes CuAlCe-O a été vérifié par comparaison avec d'autres voies de synthèses. L'activité supérieure du catalyseur CuAlCe-O peut être corrélée à un effet de synergie entre les éléments cuivre et cérium
Biomass burning, in particular wood, is an attractive alternative to the utilization of fossil fuels for energy supply, as it is renewable and does contribute to any additional CO₂ emission into atmospher. However, it is known that heating appliances using biomass generate large amounts of Volatile Organic Compounds (VOCs) and carbon monoxide (CO) during the combustion cycle. A catalytic post-treatment is one of the most promising technologies to limit the emissions of these pollutants. This project aims to develop active and selective catalytic materials with enhanced redox properties in order to achieve the total oxidation of VOCs and CO at low temperature. Noble metals based catalysts are considered as good candidates for such types of reactions. However, these catalysts are very expensive for adaptation to domestic heating device. The objective of our work is focused on the synthesis and development of innovative and cheaper catalytic materials composed of transition metal oxides that could be used as alternatives to noble metal catalysts. In order to obtain efficient oxides, the hydrotelcite route was chosen for the synthesis of the catalysts. The beneficial effect of adding cerium to MgAl-O and CuAl-O oxides towards the oxidation of toluene and/or CO was demonstrated. A relationship between the reducibility and activity of these solids for these reactions has been also identified. For MgAlCe-O catalysts, a beneficial effect on the conversion of toluene in presence of CO was observed. Indeed, the temperature of toluene oxidation was shifted at lower temperatures in presence of CO. In contrary, no effect on toluene conversion was observed for the CuAlCe-O materials. However, a significant effect on the conversion of CO in presence of toluene was revealed. Briefly, a CuAlCe-O type oxide with high activity and stability has been synthesized for the destruction of VOCs and CO mixtures. In addition, the advantage of using the hydrotalcite route to synthesize these CuAlCe-O oxides has been verified by comparison with other synthetic routes. The high activity of the CuAlCe-O catalyst can be attributed to the synergic effect between copper and cerium elements

Orientador: Telma Teixeira Franco
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
Made available in DSpace on 2018-08-21T16:33:14Z (GMT). No. of bitstreams: 1 Piovani_MonicaRegina_D.pdf: 3018875 bytes, checksum: fd8c35c2204ec9208757e570785a6b90 (MD5) Previous issue date: 2012
Resumo: As microalgas são microrganismos que vem sendo utilizados na bioconversão de carbono em produtos com interesse comercial como, por exemplo, biocombustíveis, corantes, suplementos alimentares e cosméticos. Elas podem ser cultivadas em sistemas autotróficos e heterotróficas sendo que as fontes de carbono, gasosas ou líquidas, podem ser provenientes de resíduos industriais reduzindo os custos de sua produção. Para identificar quais os possíveis produtos gerados durante o cultivo o objetivo deste trabalho foi avaliar a bioconversão de dióxido de carbono em fotobiorreatores identificando os principais bioprodutos gerados nas fases sólida, líquida e gasosa do sistema. Os experimentos foram conduzidos em fotobiorreatores de coluna de bolhas, alimentados com meio de cultivo sintético, com microalga C. vulgaris em fase exponencial de crescimento. Foi utilizado reator isotérmico, intensidades luminosas de 150?.molm-2.s-1, e injeção de ar com dióxido de carbono na vazão de 1Lmin-1. Além da conversão de carbono foram avaliados métodos de extração de lipídeos baseados no método de Bligh & Dyer e métodos gravimétricos para determinação do teor de umidade. A conversão de CO2 nos sistemas utilizados foi avaliada nas fases sólida, líquida e gasosa e foi expressa em termos de produção de biomassa (6%), em compostos solúveis na fase líquida, e composta orgânicos voláteis (88%) liberados para fase gasosa do sistema. O teor de umidade da biomassa das microalgas foi de 85% para os métodos avaliados e para os métodos para extração de lipídeos foi possível observar a influência do teor de umidade na biomassa na porcentagem de lipídeos que teve variação de 3% a 24%
Abstract: Microalgae are microorganisms that have been used for bioconversion of carbon into products of commercial interest such as, biofuels, pigments, food supplements and cosmetics. They can be grown in autotrophic and heterotrophic systems and the carbon sources, gaseous or liquid, can be derived from industrial wastes, reducing the costs of production. To identify the possible products generated during the culture the objective of this study was to evaluate the bioconversion of carbon dioxide in photobioreactors identifying key byproducts in solid, liquid and gaseous phases the generated in system. The experiments were conducted in bubble column photobioreactors, fed synthetic growth medium, and C. vulgaris cultures in exponential growth phase. The reactor was operated isothermically with 150?molm-2s-1 of light intensities and injection of air with carbon dioxide in the flow 1Lmin-1. Besides the carbon conversion, were evaluated lipid extraction methods based on the Bligh & Dyer's method and gravimetric methods for determination of moisture content. The conversion of CO2 systems will be evaluated in phases solid, liquid and gaseous systems, expressed in terms of biomass (6%), production in soluble compounds in the liquid phase and volatiles organic compounds released into the gaseous phase. The moisture content of microalgae biomass was 85% for the evaluated methods and for the extraction of lipids methods was possible to observe the influence of moisture content in the percentage of lipids that ranged from 3% to 24%
Doutorado
Desenvolvimento de Processos Químicos
Doutora em Engenharia Quimica

L'extraction au dioxyde de carbone supercritique des composes volatils s'est revelee efficace en maintenant des conditions experimentales moderees (cent cinquante bars, trente six degres). On a tente de remedier aux pertes en ajoutant dans l'appareil au niveau du separateur, differents milieux de piegeage (huile, glycerol, cyclodextrines) pouvant retenir les composes volatils. Un des interets de ces milieux reside dans la possibilite de les utiliser directement dans le domaine de l'agro-alimentaire. Les milieux se sont reveles, chacun avec sa specificite, capable d'ameliorer la recuperation des composes volatils, tant a partir d'une solution modele que d'un jus de framboise. On a egalement identifie par chromatographie en phase gazeuse et spectrometrie de masse des composes issus de reactions secondaires dues aux fortes pressions

Volatile organic compounds (VOCs) are organic compounds which exist in the gas phase at room temperature and atmospheric pressure. The lifespan of VOCs in the Earth's atmosphere ranges from a few minutes to months. Many VOCs are dangerous to human health and can undergo oxidation mediated aggregation to form secondary organic aerosols which are equally detrimental to human health. VOCs come from biogenic and anthropogenic sources, however, in cities, anthropogenic sources are dominant. A significant portion of these anthropogenic VOCs are coming from diesel vehicle emissions. Chemical composition of VOCs from diesel exhaust is complex and varies with the engine technology, driving conditions and fuel used. Previously, VOCs have been measured using offline methods which required sample collection over a period (making it difficult to capture their temporal variability) and sample preparation (making the whole process time-consuming). The development of online mass spectrometrybased measurement techniques enabled monitoring VOCs in real time. Real time measurement of VOCs from the atmosphere is based on chemical ionisation mass spectrometry with hydronium ions as reagent ions. This was because hydronium ion allows the instrument to detect compounds that have proton affinity (PA) higher than that of water. Normal air components like N2 and O2 all have PA lower than water, however most of the saturated and unsaturated volatile organic compounds emitted from diesel exhaust have PA higher than water. The most commonly used instruments for atmospheric VOC measurement are Proton Transfer Reaction-Mass Spectrometer (quadrupole and Time of Flight), Selective Ion Flow Tube-Mass Spectrometer. The Aerodyne Chemical Ionisation Mass Spectrometer (CIMS) is a more recent instrument that allows the use of different reagent ions including hydronium ion H3O+. While both PTR-MS and SIFT-MS ionise samples at relatively low pressure (1-2 mbar) and their ionisation chambers been extensively studied, ion-Molecule Reaction (IMR) chamber in H3O+-CIMS operates at substantially higher pressure (~100 mbar) and, therefore, reagent ion distribution and ionisation chemistry are likely to be significantly different from the ones in PTR-MS and SIFT-MS. However, performance of the H3O+-CIMS has not been characterised in detail yet nor has this instrument been applied to investigate VOCs coming from diesel exhaust. This study is, therefore, aimed at characterising the performance of Aerodyne TOF-CIMS with H3O+ as reagent ions, herein referred to as H3O+-CIMS and later using the same for characterisation of diesel exhaust VOCs. In characterising the H3O+-CIMS, the influence of the pressure inside the IMR chamber and SSQ (small sequential quadrupole) chamber on the intensity of reagent ions was explored. It was found that the optimum pressures for IMR and SSQ were ≥ 160 mbar and ≥ 2.3 mbar respectively. Exploration of radio frequency (RF) voltages of quadrupole ion guides inside the atmospheric pressure interface showed that 200V for the SSQ and 350V for the big sequential quadrupole (BSQ) are the optimum RF voltages for obtaining a maximum reagent ion signal intensity. The sensitivity of the instrument towards some common VOCs was determined using a custom-made VOC mixture. It was found that H3O+-CIMS was more sensitive to oxygenated VOCs compared to non-oxygenated VOCs. The sensitivity to oxygenated VOCs was comparable to PTR-MS and SIFT-MS while it was lower for non-oxygenated VOCs. It was also observed that relative humidity of the incoming air influences VOCs signal intensity with different compounds showing different RH dependence. Hydrate formation was explored as PTR-MS and SIFT-MS have both shown the formation of hydrate with increase in humidity. In dry conditions with RH of 5%, hydrates were not formed for both non-oxygenated and oxygenated VOCs (NO-VOCs and O-VOCs respectively) except for acetonitrile with hydrate composition of ~7 – 25%. However, as RH increased to ~90%, hydrate composition was 10% 60% for NO-VOCs and ~ 3% to 4% for oxygenated VOCs. The instrument was tuned using 2 different tuning approaches - one aimed at maximising m/z 19 signal (H3O+) relative to the m/z 37 signal (H5O2 +) which maximises ion declustering and the other aimed at maximising m/z 37 signal (H5O2 +) relative to m/z 19 signal (H3O+) which minimises ion declustering. It was found that reagent ions and VOC signals were the highest with m/z 19 tuning approach. After characterisation, the H3O+-CIMS was used to investigate VOCs from diesel exhaust. A total of 256 peaks were identified within a m/z range 15Th – 200Th, could not go beyond m/z 200 because peak resolution becomes very difficult beyond this point. 179 VOCs remained after the background had been subtracted, 44 of these VOCs were non-oxygenated hydrocarbon species, 79 were oxygenated species, 50 were nitrogen containing species and 9 were sulphur containing species. VOC emissions from 3 diesel engines (Perkins, Kubota and Cummins) running on neat diesel fuel were compared. Cummins engine was found to emit the least number of VOCs in m/z 15 – 200 range which might be because it uses a common rail injection system unlike the other two engines, which utilise direct injection. When VOC emissions from neat diesel (D100) were compared with neat biodiesel (B100) using 3 diesel engines, benzene, toluene and xylene emissions were higher in B100 compared to D100 in all the engines. Similar trend was observed for CH5O+, C2H5O+, C4H5O+ and C5H9O+. This may be due to higher oxygen content in biodiesel compared to diesel fuel. However, a set of measurements was conducted where oxygen content of the fuel was varied by the use of biodiesel blends and it was shown that increasing the oxygen content of the fuel does not necessarily translate to increase in emissions of oxygenated VOCs. The role of oxygen content in the fuel was found to be compound dependent instead. It was also found that benzene, toluene and xylene emissions generally decreased with increase in oxygen content. The contribution of this study to knowledge is that H3O+ -CIMS with IMR inlet is a useful tool in analysing VOCs emitted from diesel exhaust. This study is among the few studies that have identified hydrogen cyanide to be among the VOCs emitted from diesel exhaust. It also showed that neat biodiesel had the highest number of oxygenated VOCs peaks despite the diesel engine used. Lastly, it was shown that increasing the oxygen content of the fuel does not necessarily mean that oxygenated VOC emissions will increase.

With the need for excellent living standards to escalate day by day, the need to breathe good quality air remains of paramount importance for a prosperous, happy life. The indoor air quality picture is improving decade by decade. However, the importance of maintaining good indoor air quality remains unsatisfactory. Indoor air quality is one of the world’s most significant environmental problems. Statistics states that as of 2017, approximately 1.6 million premature deaths are caused by bad indoor air quality. The majority of these deaths result from the presence of Volatile Organic compounds in the air. VOCs are the common pollutants that are found indoors, which are not only toxic but also dangerous to health on long exposures. Even though several norms are put in place, why is the picture still persistent even after many technological advancements in the industry? This notion of this idea inspired the authors to conduct the current thesis. The thesis is based on a case study at a Swedish Air-cleantech company, Company-X, that developed efficient air filtration technologies to eliminate VOCs from the indoor air. However, for efficient diffusion of the technology, studying the market is of utmost importance. For this, the study is done by qualitative interviewing of professionals from the Swedish air filtration market. The interactions helped the authors to comprehend the more in-depth picture of influencing facets in persistent VOC issues in the indoor airs. Secondly,the meetings guided the authors with the industry choice for efficient technologies to eliminate VOCs from the indoor air. The collected data led to the conclusions that, various actors like awareness and buying decision factors, technologies are involved for VOCs still being a persistent issue in indoor airs. The industry’s awareness regarding Volatile Organic Compounds has been mediocre, and the significant factor for the buying decision is the price. Speaking of the technology, it has been reckoned that Activated Carbon filters are the best and economically efficient technology to eliminated VOCs from the air.

Thesis (MSc) -- Macquarie University, Division of Environmental and Life Sciences, Dept. of Chemistry and Biomolecular Sciences, 2008.
Bibliography: p. 120-124.
Introduction -- Environmental factors affecting the emission of biogenic Volatile organic compounds -- Materials and experimental procedures -- Quantification using sold-phase microextraction in a dynamic system: technique development -- The emission profile of Tristaniopsis laurina -- Study of the effect of elevated atmospheric CO₂ levels on the emission of BVOCS from Australian native plants -- Conclusions and future work.
Biogenic Volatile Organic Compounds (BVOCs) emitted by plants can affect the climate and play important roles in the chemistry of the troposphere. As ambient atmospheric carbon dioxide (CO₂) levels are rapidly increasing knowledge of the effect of elevated atmospheric CO₂ on plant BVOC emissions is necessary for the development of global climate models. -- During this study, the effect of elevated atmospheric CO2 mixing ratios on BVOC emissions from Corymbia citriodora (Lemon Scented Gum) and Tristaniopsis laurina (Water Gum) was determined for the first time through the combination of Solid-Phase Microextraction (SPME), Gas Chromatography-Flame Ionisation Detection (GC-FID), Gas Chromatography-Mass Spectrometry (GC-MS) and an environment chamber. For C. citriodora elevated atmospheric CO₂ led to a decrease in the emission rate of α-pinene, β-pinene, eucalyptol, citronellal and β-caryophyllene, however, elevated CO₂ had no effect on the emission rate of citronellol. The emission profile of T. laurina has been determined for the first time. For T. laurina elevated CO₂ led to a decrease in the emission rate of α-pinene but the emission rates of β-pinene, limonene, eucalyptol and citronellol were unaffected. The results obtained in this work confirm that the effect of elevated atmospheric CO₂ on plant BVOC emissions is species-specific.
Mode of access: World Wide Web.
124 leaves ill. (some col.)

Depuis la révolution industrielle les niveaux des concentrations atmosphériques des gaz à effet de serre ne cessent d’augmenter provocant ainsi une accélération du réchauffement climatique. Les composés organiques volatils (COVs) contribuent non seulement à cet effet de serre mais aussi à la pollution environnementale qui a un impact négatif sur toutes les espèces vivantes de la planète. Par exemple, au cours de l’année 2012, la pollution de l'air a été à l’origine 7 millions de décès, selon l'Organisation mondiale de la santé (OMS) [1]. Très récemment, une étude médicale de la commission Lancet sur la pollution et la santé a révélé qu'en 2015 un décès sur six était lié à la pollution de l'air et de l'eau, 6,5 millions de décès dans le monde chaque année sont liés à la pollution de l'air intérieur et extérieur [2]. En effet, les COVs, très volatils et utilisés comme solvants par exemple, peuvent être indirectement à l’origine de toux, d’inconfort thoracique, de gêne douloureuse, d’essoufflement respiratoire, d’irritation nasale ou oculaire ou encore de la gorge. Ils peuvent aussi être directement toxiques ou explosifs ou encore perturbateurs de la réponse immunitaire. De plus certains d’entre eux sont classés CMR (cancérogène, mutagène et reprotoxique). Dans ces conditions une meilleure connaissance des effets liés à l’exposition aux COVs sur la santé et l’environnement est vraiment nécessaire. Cette connaissance passe également par la détection et la quantification des concentrations de COVs afin de proposer un meilleur aménagement des environnements et d'alerter les individus concernés en temps réel sur les dangers encourus. La plupart des plateformes déjà existantes ou commercialisées sont soient trop coûteuses, soient très consommatrices d'énergie, soient fonctionnelles à des températures élevées, soient instables pour la détection en temps réel ou à long terme ce qui limite la prolifération des sites de mesures. Ainsi, cette thèse s’inscrit dans le domaine des capteurs de gaz dédiés pour la détection de la pollution dans l’air. Elle porte sur le développement d’une plateforme de détection, de suivi et de quantification des composés organiques volatils (COVs) en temps réel, utilisant un capteur de gaz différentiel flexible et imprimé basé sur des transducteurs micro-ondes et des matériaux carbonés polymères composites comme couches sensibles. Le dispositif proposé vise à fournir des informations directement exploitables pour constituer à terme une plateforme de faible coût embarquée, dédiée à l’internet des objets pour faciliter la prolifération des sites de détection et de contrôle en réalisant des réseaux de capteurs communicants sans fil fonctionnant en environnements variés
Since the Industrial Revolution, the levels of atmospheric concentrations of greenhouse gases have been increasing, causing an acceleration of global warming. Volatile organic compounds (VOCs) contribute not only to this greenhouse effect, but also to environmental pollution, which has a negative impact on all living species on the planet. For example, in the year 2012, air pollution caused 7 million deaths, according to the World Health Organization (WHO) [1]. In addition, a very recent medical study by the Lancet Commission on Pollution and Health found that one in six deaths in 2015 was related to air and water pollution [2]. Also, indoor and outdoor air pollution is linked to 6.5 million deaths worldwide each year. VOCs can indirectly cause cough, chest discomfort, painful discomfort, shortness of breath, as well as nasal, ocular or throat irritation. They can also be directly toxic or explosive or disruptive of the immune response. In addition, some of them are classified as CMR (carcinogenic, mutagenic and reprotoxic). They are very volatile and often used as solvents for example. In these conditions, a better understanding of the health and environmental effects of exposure to VOCs is necessary. Such knowledge also involves the detection and quantification of VOC concentrations in order to propose a better management of the environments and to alert people in real time of the dangers incurred. Most of the existing or commercially available platforms are either too expensive, energy intensive, high temperature functional, unstable for real-time or long-term detection, which limits the proliferation of measurement sites. This thesis is in the field of dedicated gas sensors for the detection of pollution in the air. It deals with the development of a platform for the detection, monitoring and quantification of volatile organic compounds (VOCs) in real time, using a flexible and printed differential gas sensor based on microwave transducers and composite polymeric carbon materials as sensitive layers. The proposed device aims at providing directly exploitable information such as a low-cost embedded platform dedicated to the Internet of things and which offers increasing possibilities for the proliferation of detection and control sites by realizing networks of wireless communicating sensors operating in various environments

Dans cette thèse, nous présentons des travaux complémentaires conduits à ICARE-CNRS (Orléans), partie A et à l’Université de Fudan (Shanghai), partie B. Partie A : les 2-et 3-carène sont deux composés organiques volatils biogéniques importants présents dans l’atmosphère dont les voies de dégradation sont encore mal connues. Afin de déterminer les constantes de vitesse des réactions de ces espèces avec l’ozone, nous avons utilisé trois systèmes expérimentaux complémentaires : des chambres de simulation d’ICARE de 7300L et 80000L (HELIOS) et un réacteur à flux laminaire. Les rendements de certains produits de réactions, le radical hydroxyle (OH), le formaldéhyde (HCHO) et le monoxyde de carbone (CO) ont aussi été déterminés. D’autre part, pour avoir une meilleure compréhension d’intermédiaires de réaction formés lors de l’ozonolyse, appelés intermédiaires de Criegee, un réacteur à flux laminaire à deux étages a été mis en place pour mesurer leurs constantes de vitesse de réaction avec SO2, NO2 et O3. Partie B : les impacts du “black carbon (BC)” et du “brown carbon (BrC)” constituent une incertitude majeure dans les modèles climatiques actuels. Des rapports récents indiquent que la morphologie et l’évolution des BC et BrC dans l’atmosphère jouent un rôle important sur la capacité d’absorption de ces particules. Afin d’étudier leurs comportements, des mélanges de particules (BC-BrC) ont été exposés en chambre de simulation atmosphérique à l'acide sulfurique, au mélange ammoniac / triéthylamine, et à la vapeur d'eau de manière séquentielle
In this thesis, we present a complementary work conducted at ICARE-CNRS (Orléans), Part A and at Fudan University (Shanghai), Part B. Part A: 2-and 3-carene are two important biogenic volatile organic compounds present in the atmosphere. The knowledge on their degradation pathways and the corresponding products are still poor. Using complementary reaction systems-ICARE 7300 L and HELIOS 80000 L simulation chambers, vertical laminar flow reactor, their kinetic rate constants for reaction with ozone were determined. Additionally, important product formation yields, hydroxyl radical (OH), formaldehyde (HCHO) and carbon monoxide (CO) have been determined with indication to their corresponding formation routes from the ozonolysis of carene. To have a better understanding on reactions of Criegee intermediates (CIs) generated through ozonolysis in the atmosphere, a horizontal 2-stage laminar flow reactor was set up to measure the rate constants of CIs with SO2, NO2 and O3. Part B: Radiative forcing of black carbon (BC) in the atmosphere, as well as that of brown carbon (BrC), remains to be a major uncertainty in current climate models. Recent reports indicate that the absorption enhancement of BC and BrC particles is determined by evolution of morphology and mixing state during the atmospheric processing. Laboratory-generated BC-BrC mixture particles (BC-BrC) were exposed to sulfuric acid, ammonia/triethylamine, and water vapor sequentially to investigate the alternation in light absorption, morphology and mixing state during simulated atmospheric processing

O Mercado Municipal de São Carlos é um centro comercial bastante importante, reunindo diversos tipos de lojas e serviços. Um grande número de pessoas frequenta o local diariamente, além de ser o ambiente de trabalho de vários comerciantes. Foi realizado diagnóstico da qualidade do ambiente interno do Mercado Municipal da cidade de São Carlos/SP, através do monitoramento dos seguintes parâmetros: MP10; MP2,5; \'CO IND.2\'; CO; COV; temperatura; umidade relativa e ruído. As coletas de dados foram realizadas durante o ano de 2011. Para todos os parâmetros analisados foram escolhidos 12 pontos amostrais internos e um ponto amostral externo, com exceção do ruído, que teve 9 pontos internos. Os dados amostrais internos de MP10 e de MP2,5 revelaram concentrações médias de 44,55 \'mü\'g/m³ e 31,96 \'mü\'g/m³, respectivamente. As concentrações externas médias foram de 35,60 \'mü\'g/m³ para MP10 e de 25,91 \'mü\'g/m³ para MP2,5. As concentrações médias observadas de material particulado estiveram abaixo dos valores recomendados pela OMS. A razão MP2,5/MP10 esteve acima de 70% indicando predominância de particulado superfino na fração MP10 do material particulado em suspensão. Análises químicas por fluorescência de raios-X foram realizadas no material particulado coletado e os elementos químicos identificados foram: Si, Al, S, Ca, Fe, Ti, Cu, Zn e V. Observou-se que os dados de \'CO IND.2\' ficaram abaixo do limite recomendado pela Resolução ANVISA 09, que é de 800 ppm, os dados internos também foram maiores que os externos. Para o CO e COV, os pontos com maiores concentrações foram os próximos dos acessos ao Mercado pela Rua Episcopal, sendo também maiores os dados internos que o externos. Os dados de temperatura e umidade relativa se mostraram, em geral, fora das faixas de recomendações da Resolução ANVISA 09, o que indica que o ambiente interno do Mercado pode ser desconfortável em relação a esses dois parâmetros. Os níveis internos de ruído observados estiveram acima daqueles recomendados pela Norma Técnica L11.032 (CETESB), que é de 50 dBA. Obteve-se pontos com médias acima de 70 dBA, evidenciando que o local é ruidoso, o que pode acarretar problemas à saúde de seus frequentadores.
The Municipal Market of São Carlos city is a very important commercial center, bringing together different types of shops and services. A large number of people attends the local daily, and it is the work environment of several merchants. A diagnostic of the quality of the indoor environment of the Municipal Market of Sao Carlos/SP was conduct, by monitoring the following parameters: PM10, PM2,5; \'CO IND.2\', CO, VOCs, temperature, humidity and noise. The data collections were performed during the year 2011. For all analyzed parameters were chosen 12 sampling indoor points and an outdoor point, with the exception of noise, which had 9 indoor points. The indoor data of PM10 and PM2,5 showed average concentrations of 44.55 \'mü\'g/m³ and 31.96 \'mü\'g/m³, respectively. The outdoor medium concentrations were 35.60 \'mü\'g/m³ for PM10 and 25.91 \'mü\'g/m³ for PM2,5. The average concentrations of particulate matter observed were below the values recommended by WHO. The reason MP2,5/MP10 was above 70%, indicating the predominance of fine particulate matter at the PM10 fraction. Chemical analysis by X-rays fluorescence was performed in the particulate matter collected and the chemicals identified were: Si, Al, S, Ca, Fe, Ti, Cu, Zn and V. It was observed that the \'CO IND.2\' data were below the limit recommended by ANVISA Resolution 09 which is 800 ppm, the indoor data were also higher than outdoor data. For CO and VOCs, the points with the highest concentrations were the ones near the accesses to the Market by the Episcopal Street, and also higher indoor data that the outdoor. The data of temperature and relative humidity proved generally outside the ranges of the recommendations ANVISA Resolution 09, which indicates that the indoor environment of the market may be uncomfortable considering these two parameters. The indoor noise levels were observed above those recommended by the Technical Standard L11.032 (CETESB), which is 50 dBA. There were some points with averages above 70 dBA, showing that the Market can be a noisy environment, which can cause health problems for their users.

Poluentes atmosféricos como nanopartículas (N), black carbon (BC) e compostos orgânicos voláteis (COVs) são de importante compreensão para a saúde infantil devido às suas propriedades cancerígenas (N, COVs e BC), bem como podem ser causados ou intensificados sintomas irritativos (COVs e BC), cefaleia, asma, doenças pulmonares e cardíacas (BC). As partículas muito pequenas (N) ainda podem atingir os sistemas cardiovascular e cerebrovascular, e até mesmo prejudicar o desempenho escolar e cognitivo das crianças. Neste contexto, o objetivo deste trabalho foi estudar a qualidade do ar indoor (sala de aula) e outdoor (portão de acesso) em escolas, onde as crianças permanecem expostas aos poluentes por um longo período, e comparar os níveis entre os ambientes. Para isso, selecionamos duas escolas da Região Metropolitana de Porto Alegre – RMPA: uma em área urbana (Canoas); e outra em área rural (Nova Santa Rita); nas quais foram realizadas 11 campanhas quinzenais de amostragem dos poluentes atmosféricos estudados entre julho e dezembro de 2016. Em complemento, foram medidos NOx, NO2, NO e O3 e variáveis meteorológicas (temperatura, umidade relativa, radiação solar e velocidade do vento) coletados na RMPA. Foram aplicadas técnicas de sensoriamento remoto para a obtenção de imagens dos filtros de BC através de MEV. Os resultados apontam que no ambiente externo - outdoor da escola urbana os níveis máximos de BC e N ocorreram nas horas de rush, devido aos altos níveis das emissões veiculares. Na escola de Nova Santa Rita os níveis de BC e N foram ligeiramente mais baixos, possivelmente por ser um ambiente com pouca influência de fontes de emissão veicular. Por outro lado, os COVs apresentaram maiores concentrações no ambiente interior - indoor das duas escolas, as fontes de emissão destes se encontram dentro das salas de aula e não estão relacionadas com as fontes externas, ou seja, a geração dos COVs é independente de ter fontes de poluição urbana ou rural. Os níveis de BC em área urbana são regidos por fontes de emissões veiculares (outdoor), as quais são facilmente transferidas para o ar indoor, para onde podem carregar consigo outras partículas (contendo, por ex., Fe); além disso, sua dispersão é dificultada em dias frios e com menor velocidade do vento. Enquanto isso, as concentrações de COVs e N são determinadas por uma influência combinada de fontes de emissão, processos secundários de formação e meteorologia, refletindo em maior sensibilidade sob diferentes condições atmosféricas tanto outdoor quanto indoor nas áreas urbana e rural. Importa ressaltar que os dirigentes de escolas rurais devem estar atentos quanto aos níveis de COVs nas salas de aula; enquanto as escolas de centros urbanos devem triplicar a atenção, pois além de COVs há concentrações expressivas de N e BC decorrentes de emissões veiculares, principalmente nas horas de rush que coincidem com o início e fim das aulas, quando as crianças permanecem no outdoor diretamente expostas à poluição veicular.
Air pollutants as nanoparticles (N), black carbon (BC) and volatile organic compounds (VOCs) may have short and long-term adverse health effects, especially when it comes to children’s health. These pollutants are known to cause cancer and other health effects may include also eye, nose and throat irritation (VOCs and BC), headaches, asthma, pulmonary and cardiovascular diseases (BC). Air-pollution-sized nanoparticles (N) can also affect cerebrovascular system. It can negatively affect students’ learning and children’s cognition. The aim of this study was to verify and compare the indoor (classrooms) and outdoor (access gates) air quality in different schools, where the children remain exposed to air pollutants for long hours per day. Two schools in different areas of Porto Alegre Metropolitan Region (RMPA) were chosen: the first one in an urban area (Canoas) and the second one in a rural area (Nova Santa Rita). Eleven fortnightly samplings were conducted to evaluate N, BC and VOCs levels between July 2016 and December 2016. We also used data of gaseous pollutants (O3, NOx, NO2, and NO) and meteorological data (temperature, relative humidity, solar radiation and wind speed) collected in the same area. Remote sensing techniques and a scanning electron microscope (SEM) were used to obtain images of the black carbon filters. In the outdoor site of the urban school, the maximum levels of BC and N were registered in the rush hours due to a high level of vehicular carbon emissions. The lower levels of BC and N in Nova Santa Rita were attributed to the fact the school is located in a rural area, which assumes a less impacted environment. Nevertheless, this study indicates that these compounds are generated during the classroom activities, since the VOCs levels were higher in the two schools indoor sites. The black carbon particles in the urban area come from vehicle emissions (outdoor) and are easily transferred to the school indoor areas. These emissions can also carry other particles (e.g., Fe) and its dispersion can be hampered in cold days with low wind speed. VOCs and N concentrations are site-independent compounds influenced by several emission sources, reactions of primary pollutants and meteorology. It causes them to reflect with a high sensibility in different atmospheric conditions both in urban and rural areas (indoor and outdoor). We would like to emphasize that both rural and urban schools managers should be aware of the risks involving air pollutants in the classroom (especially VOCs). Urban schools boards should also remain vigilant on the expressive concentrations of N and BC near their access gates, arising from vehicle carbon emissions, which represents a risk for the children’s health.

Black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) are two atmospheric pollutants produced by motor vehicles using carbonaceous fuels. As a part of the Mexico City Project, measurements of BC, PPAHs and many other gas- and particle-phase emissions were measured in Mexico City using a mobile laboratory during the Mexico City Metropolitan Area field campaign in April 2003 (MCMA-2003). The main goal of this research is to estimate emissions of BC and particulate PAHs (PPAHs) for Mexico Cityâ s vehicle fleet. The emissions of gas-phase pollutants such as carbon monoxide (CO), total nitrogen oxides (NOy) and volatile organic compounds (VOC) are also estimated. The mobile lab has previously been used to chase vehicles and measure their emissions, but analysis has traditionally focused on determining emission factors of individual vehicles associated with specific chasing events. The laboratory continuously samples ambient air from an inlet at the front of the van, and it is always â seeingâ exhaust plumes from the vehicles around it while driving through traffic. We have developed an algorithm that automatically identifies the exhaust plume measurement points, which are then used as the basis for calculation of emission factors. In the nearly 90 hours of on-road sampling during the field campaign, we have identified ~30,000 exhaust measurement points. The large sample size enables us to estimate fleet-average emission factors and thus the emission inventory. Motor vehicles are estimated to emit annually 1,960 tons of BC, 56.2 tons of PPAHs, 1,320,000 tons of CO, 125,000 tons of NOy and 2440 tons of VOCs. The spatial and temporal patterns of BC and PPAHs in different locations with in MCMA are also studied.
Master of Science

This thesis is an evaluative study of air pollution emissions from different sources in Australia and overseas. It investigates indoor and outdoor sources, including indoor combustion, electric equipment, asphalt pavement, forest fires and vehicular traffic. Based on evaluating sources, a simple practical method is proposed to identify pollution sources. This research has important scientific implications and potential for future practical applications, given the paucity of quantitative air quality studies available for pollution control.

Plants emit a diverse range of biogenic volatile organic compounds (BVOCs) into the atmosphere, of which isoprene is the most abundantly emitted. Isoprene significantly affects biological and atmospheric processes, but the range of isoprene and BVOCs present in bamboos has not been well characterized. In this thesis I explore the range of isoprene emission found in bamboos and relate it to plant morphological and physiological characteristics. In addition, I measure and relate the entire suite of BVOCs present in the bamboos to their fundamental isoprene emission rate. Interspecific variation in isoprene emission documented in a comprehensive survey of bamboos. Two groups of bamboo species were measured in the greenhouse and the field. Elevated photosynthetic rate was significantly correlated with isoprene emission. In the field, dark respiration rate was highest in bamboos that made the least amount of isoprene. The total BVOC suite was significantly influenced by whether or not leaf-level isoprene emission was present. I conclude that bamboos vary with regard to physiology, morphology, and total BVOC suite and that isoprene emission is correlated with these changes, and introduce the bamboos as a novel system for studying the impacts of isoprene emission.

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Emerging supercritical carbon dioxide (SCCD) technology has been studied as a cold pasteurizing agent, however, few studies are available on its efficiency in dairy products. In this study, the effects of SCCD processing by different pressures 14, 16 and 18 MPa (35 ? 2 ?C / 10 min) on whey drink, whey drink and grape juice were investigated in comparison To conventional pasteurization (heat treatment at 72 ?C / 15 s). Physicochemical analyzes of pH, titratable acidity, total soluble solids, phenolic compounds, anthocyanins, antioxidant activity, angiotensin converting enzyme (ACE) inhibitory activity and volatile compounds were performed. The color, particle size, rheology, physical stability, as well as microbiological quality and sensory analysis of beverages were also smoothed. The results of this study evidenced the absence of differences between treatments in pH, titratable acidity, soluble solids, total anthocyanins and DPPH activity (p> 0.05). A direct relationship between SCCD pressure and ACE inhibitory activity was observed, with 34.63, 38.75 and 44.31% (14, 16 and 18 MPa, respectively). Few differences were found in the volatile compounds profile. The beverage processing by SCCD resulted in a product with lower particle diameter, lower consistency index and a reduction in pseudoplastic character compared to the beverage treated by the conventional process. No effect of high pressure CO2 on the sensorial attributes of the drink was observed for the studied levels. Consumers found no difference between CO2 treated beverages and heat-treated beverages. The results confirm the processing of SCCD as a promising technology for the non-thermal treatment of grape whey drink made available a health and wellness promoter beverage. Background: Non-thermal food processing is configured as an interesting alternative for the food industry due to the increased nutrient retention and minimal sensory changes in processed products. Scope and approach: The aim of this review is to address the potential of supercritical carbon dioxide technology, emphasizing milk and dairy processing, including the historical aspects, main advantages, microbial inactivation mechanisms, as well as effects in some quality parameters of dairy products. Key findings and conclusions: The use of supercritical carbon dioxide technology (SC-CO2) presents great potential application in dairy processing, since it is effective to reduce microbial load when compared to the pasteurization process, thus obtaining a product with greater shelf life and better organoleptic properties with minimal and sometimes positive changes in the intrinsic quality parameters The effect of supercritical carbon dioxide technology (SCCD, 140, 160, and 180 bar at 35 ? 2 ?C for 10 min) on whey-grape juice drink characteristics was investigated. Physicochemical characterization (pH, titratable acidity, total soluble solids), bioactive compounds ( phenolic compunds, anthocyanins , DPPH and ACE activity) and the volatile compounds were performed. Absence of differences were found among treatments for pH, titratable acidity, soluble solids, total anthocyanins and DPPH activity (p>0.05). A direct relationship between SCCD pressure and ACE inhibitory activity was observed, with 34.63, 38.75, and 44.31% (140, 160, and 180 bar, respectively). Regards the volatile compounds, it was noted few differences except by the presence of ketones. The findings confirm the SCCD processing as a potential promising technology to the conventional thermal treatment. The use of supercritical technology as a non-thermal pasteurization process of the whey-grape juice drink was investigated in this study. The effects of supercritical carbon dioxide at 14, 16, and 18 MPa (35 ? 2?C/10 min) on the physical and sensory properties of the beverage, when compared to conventional pasteurization (heat treatment at 72?C/15 s) were evaluated. High-pressure CO2 processing of whey-grape juice drink resulted in a product with lower particle diameter, lower consistency index, and a reduction in pseudoplastic character when compared to the beverage treated by the conventional process. No effect of high-pressure CO2 was observed on the sensory attributes of the beverage for the levels studied. Consumers did not find differences between the CO2-treated and heat-treated beverages. Our findings suggest the use of supercritical technology with carbon dioxide as an effective alternative for the production and availability of a health and wellness promoting beverage
A tecnologia emergente de di?xido de carbono supercr?tico (DCSC) vem sendo estudada como agente pasteuriza??o a frio, no entanto, s?o poucos os estudos dispon?veis a cerca da sua efici?ncia em derivados l?cteos. Neste estudo, foram investigados os efeitos do processamento do DCSC por diferentes press?es 14, 16 e 18 MPa (35 ? 2 ?C / 10 min) no whey drink de uva, bebida a base de soro de leite e suco de uva, em compara??o ? pasteuriza??o convencional (tratamento t?rmico a 72 ?C / 15 s). Foram realizadas an?lises f?sico-quimicas de pH, acidez titul?vel, s?lidos sol?veis totais, compostos fen?licos, antocianinas, atividade antioxidante, atividade inibidora da enzima conversora de angiotensina (ECA) e compostos vol?teis. Tamb?m foramam alisados a cor, o tamanho de part?cula, reologia, estabilidade f?sica, assim como a qualidade microbiol?gica e analise sensorial das bebidas. Os resultados deste estudo evidenciaram a aus?ncia de diferen?as entre os tratamentos nas an?lises de pH, acidez titul?vel, s?lidos sol?veis, antocianinas totais e atividade de DPPH (p> 0,05). Foi observada uma rela??o direta entre press?o DCSC e atividade inibit?ria ACE, com 34,63, 38,75 e 44,31% (14, 16 e 18 MPa, respectivamente). Poucas diferen?as foram encontratdas no perfil dos compostos vol?teis. O processamento das bebidas por DCSC resultou em um produto com menor di?metro de part?cula, menor ?ndice de consist?ncia e uma redu??o no car?ter pseudopl?stico em compara??o com a bebida tratada pelo processo convencional. N?o foi observado efeito de CO2 de alta press?o nos atributos sensoriais da bebida para os n?veis estudados. Os consumidores n?o encontraram diferen?as entre as bebidas tratadas com CO2 e as bebidas tratadas termicamente. Os resultados confirmam o processamento do DCSC como uma tecnologia promissora para o tratamento n?o t?rmico de whey drink de uva disponibilizado uma bebida promotora de sa?de e bem-estar Antecedentes: Os processamentos de alimentos n?o t?rmicos s?o configurados como uma alternativa interessante para a ind?stria de alimentos devido ao aumento da reten??o de nutrientes e mudan?as sensoriais m?nimas nos produtos processados. ?mbito e abordagem: o objetivo desta revis?o ? abordar o potencial da tecnologia de di?xido de carbono supercr?tico, enfatizando o processamento de leite e l?cteos, incluindo os aspectos hist?ricos, as principais vantagens, os mecanismos de inativa??o microbiana, bem como os efeitos em alguns par?metros de qualidade dos produtos l?cteos. Principais conclus?es e conclus?es: o uso de tecnologia supercr?tica de di?xido de carbono (SC-CO2) apresenta grande potencial de aplica??o no processamento de l?cteos, uma vez que ? efetivo reduzir a carga microbiana quando comparado ao processo de pasteuriza??o, obtendo-se assim um produto com maior prateleira e melhores propriedades sensoriais com mudan?as m?nimas e ?s vezes positivas nos par?metros de qualidade intr?nseca. O efeito da tecnologia de di?xido de carbono supercr?tico (SCCD, 140, 160 e 180 bar a 35 ? 2 ?C durante 10 min) em caracter?sticas de bebidas de suco de uva foi investigado. Caracteriza??o f?sico-qu?mica (pH, acidez titul?vel, s?lidos sol?veis totais), compostos bioativos (compostos fen?licos, antocianinas, DPPH e atividade ACE) e os compostos vol?teis foram realizados. A aus?ncia de diferen?as foi encontrada entre tratamentos para pH, acidez titul?vel, s?lidos sol?veis, antocianinas totais e atividade de DPPH (p> 0,05). Foi observada uma rela??o direta entre press?o SCCD e atividade inibit?ria ACE, com 34,63, 38,75 e 44,31% (140, 160 e 180 bar, respectivamente). Atende aos compostos vol?teis, observou-se poucas diferen?as, exceto pela presen?a de cetonas. Os resultados confirmam o processamento do SCCD como uma potencial tecnologia promissora para o tratamento t?rmico convencional O uso da tecnologia supercr?tica como processo de pasteuriza??o a frio da bebida de suco de uva e soro de uva foi investigado neste estudo. Os efeitos do di?xido de carbono supercr?tico em 14, 16 e 18 MPa (35 ? 2 ?C / 10 min) nas propriedades f?sicas e sensoriais da bebida, quando comparados ? pasteuriza??o convencional (tratamento t?rmico a 72 ?C / 15 s) Foram avaliados. O processamento de CO2 de alta press?o da bebida de suco de soro de soro de leite resultou em um produto com menor di?metro de part?cula, menor ?ndice de consist?ncia e uma redu??o no car?ter pseudopl?stico em compara??o com a bebida tratada pelo processo convencional. N?o foi observado efeito de CO2 de alta press?o nos atributos sensoriais da bebida para os n?veis estudados. Os consumidores n?o encontraram diferen?as entre as bebidas tratadas com CO2 e as bebidas tratadas termicamente. Nossas descobertas sugerem o uso da tecnologia supercr?tica com di?xido de carbono como uma alternativa efetiva para a produ??o e disponibilidade de uma bebida promotora de sa?de e bem-estar

This thesis reports on the results of a mobile source emissions inventory for the University of Central Florida (UCF). For a large urban university, the majority of volatile organic compounds (VOC), oxides of nitrogen (NOsubscript x]), and carbon dioxide (CO[sub2]) emissions come from on-road sources: personal vehicles and campus shuttles carrying students, faculty, staff, and administrators to and from the university, as well as university business trips. In addition to emissions from daily commutes, non-road equipment such as lawnmowers, leaf blowers, small maintenance vehicles, and other such equipment utilized on campus contributes to a significant portion to the total emissions from the university. UCF has recently become the second largest university in the nation (with over 56,000 students enrolled in the fall 2010 semester), and contributes significantly to VOC, NOsubscript x], and CO[sub2] emissions in Central Florida area. In this project, students, faculty, staff, and administrators were first surveyed to determine their commuting distances and frequencies. Information was also gathered on vehicle type, and age distribution of the personal vehicles of students, faculty, administration, and staff as well as their bus, car-pool, and alternate transportation usage. The EPA approved mobile source emissions model, Motor Vehicle Emissions Simulator (MOVES2010a), was used to calculate the emissions from on-road vehicles, and UCF fleet gasoline consumption records were used to calculate the emissions from non-road equipment and on campus UCF fleet vehicles. The results of the UCF mobile source emissions inventory are reported and compared to a recently completed emissions inventory for the entire three-county area in Central Florida.
ID: 030423247; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.Env.E.)--University of Central Florida, 2011.; Includes bibliographical references (p. 117-120).
M.S.Env.E.
Masters
Civil, Environmental and Construction Engineering
Engineering and Computer Science
Environmental Engineering

An emissions inventory of VOCs, NO[subscript x], and CO[sub2] was conducted for three central Florida counties--Orange, Seminole, and Osceola (OSO)--for calendar year 2008. The inventory utilized three programs: MOBILE6, NONROAD2005, and EDMS (Emissions and Dispersion Modeling System) to model on-road mobile, non-road mobile, and airport emissions, respectively. Remaining point and area source data was estimated from the Florida Department of Environmental Protection (FDEP) and the U.S. Environmental Protection Agency's (U.S. EPA) 2008 emissions inventory. The previous OSO emissions inventory was done in 2002 and in the six years between inventories, there have been changes in population, commerce, and pollution control technology in central Florida which have affected the region's emissions. It is important to model VOC and NO[subscript x] emissions to determine from where the largest proportions are coming. VOCs and NO[subscript x] are ozone precursors, and in the presence of heat and sunlight, they react to form ozone (O[sub3]). Ozone is regulated by the U.S. Environmental Protection Agency through the FDEP. The current standard is 75 parts per billion (ppb) and Orange County's average is 71 ppb. A new standard (which will likely be about 65 ppb) is being developed and is scheduled to be announced by July 2011. If OSO goes into non-attainment, it will need to prepare a contingency plan for how to reduce emissions to submit to the FDEP for approval. The 2008 inventory determined that approximately 71,300 tons of VOCs and 59,000 tons of NO[subscript x] were emitted that year. The majority of VOCs came from on-road mobile sources (33%) and area sources (43%), while the majority of NO[subscript x] came from on-road mobile sources (64%) and non-road mobile sources (17%).; Other major sources of VOCs included gasoline powered non-road mobile equipment (lawn and garden equipment), consumer solvents, cooking, and gasoline distribution. With the numbers that could be determined for CO[sub2] emissions, on-road mobile and point sources were responsible for 93%. Of the point source CO[sub2] emissions, almost all of it (87%) came from one large coal-fired power plant in Orange County.
ID: 029810421; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.Env.E.)--University of Central Florida, 2011.; Includes bibliographical references (p. 103-107).
M.S.Env.E.
Masters
Civil, Environmental and Construction Engineering
Engineering and Computer Science
Environmental Engineering

Air pollution is a problem affecting developing and developed countries concerned about the adverse health effects associated with exposure to indoor and outdoor air pollutants. In developing countries like India, the problem, particularly domestic air pollution, is worsened by the use of unprocessed solid fuels for cooking. Other indoor environmental risk factors include the characteristics of housing conditions, household activities, and low Socio-economic status (SES). The potential irritants include nitrogen dioxide (NO[subscript]2), formaldehyde (HCHO), volatile organic compounds (VOCs), indoor smoking, and particulate matter (PM[subscript]2.5-10) and carbon monoxide (CO).Indoor air pollutants, especially those in domestic households are major problems that can contribute to respiratory symptoms and poor health in mothers and children and, in particular, those who live in poorer households in developing countries. There is consistent evidence that mothers and young children from these countries spend more than 80% of their time indoors, especially in the kitchen. Therefore, domestic air quality may be related to the increase in the prevalence of respiratory symptoms and other allergic conditions. In this context, this study established risk factors in the domestic environment that can determine the concentrations of domestic air pollutants and prevalence of respiratory symptoms in mothers and children. Cooking for a long time, keeping young children and infants in cooking areas, the inadequacy of ventilation, and the use of biomass fuels can relate to debilitating health problems, especially respiratory symptoms among poor households’ mothers and children particularly in developing countries.This study is cross-sectional and aims to determine that domestic concentrations of fine particles (PM[subscript]2.5), carbon monoxide (CO), and the socio-economic status (SES) and/or poverty levels, house and kitchen characteristics and households’ activities, may have a detrimental role in the prevalence of respiratory symptoms among mothers and children. One hundred and seventy households (N=170) with young children (n=299) under 15-years-of-age were selected randomly from the City of Tirupur in Coimbatore district, Tamil Nadu in South India. This city was chosen as it has diversity in terms of its ethnic mix, economic activities, physical characteristics and income disparities. Each participating household was visited and 170 households’ mothers were interviewed using a questionnaire. During the visits, study data was also collected in 80 households by measuring of indoor concentrations of PM[subscript]2.5, CO and the physical parameters, humidity and temperature.According to the statistical analysis, using biomass for cooking affects mothers’ and children’s respiratory symptoms. The results of this study show that median exposure to fine particles (PM[subscript]2.5) (1.18mg/m[superscript]3) exceeds the recommended WHO standards. CO concentrations did not have any significant relationship with mothers’ and children’s respiratory symptoms as mean concentrations of CO were 4.63ppm or 8.80mg/m[superscript]3. The study shows that kitchens with brick/stone walls and tile roofs are associated with reduced concentrations of PM[subscript]2.5 (p=0.033). If a kitchen has mud walls, a thatched roof and a floor of clay/mud, the indoor air has higher concentrations of PM[subscript]2.5 (p=0.014), Floors, such as cement, can lower the domestic air concentration of PM[subscript]2.5, (p=0.014). The study finds that lower concentrations of PM[subscript]2.5 were also found when windows were open (OR=0.14), (p=0.018).The study shows that there is a significant relationship between the prevalence of asthma in children in relation to CO and more than one time (OR=1.19) with p=0.021. In this study, it was shown that mothers with lower incomes had shortness of breath (p=0.003), almost six times higher than mothers with higher incomes. Children with allergies (78.9%) in the current study came from families where the mothers were employed as labourers and their children had respiratory symptoms such as coughing (p=0.001) and wheezing (p=0.002). The most (p=0.001) significant respiratory symptom of children from families who did not own house/unit or land was a cough: 56 (42.4%) as they usually live either in semi-open air or very badly constructed dwellings).High R/H (%) and T[superscript]oC also seem to have an effect on domestic concentrations of PM[subscript]2.5. As revealed by the statistical analysis, high T[superscript]oC and RH (%) were associated with significant impacts on mothers’ respiratory symptoms but did not have any significant impact on children’s respiratory symptoms. High-income households’ mothers and children were seen to have less significant respiratory symptoms than low-income households’ mothers. Evaluation of the literature also assessed the extent to which SES and/or poverty levels and house and kitchen characteristics and households’ activities affected respiratory symptoms in mothers and children.In conclusion, this study’s results further highlight the role of susceptibility risk factors for respiratory symptoms and show that domestic environmental factors contribute as risk factors for respiratory symptoms in mothers and children, especially in poor households. In order to improve domestic air quality and thus decrease the prevalence of respiratory symptoms, much more effort needs to be made. Because the air quality in the domestic environment is modifiable, there may be opportunities for intervention to reduce respiratory symptoms and this needs greater attention. Low SES and/or poverty levels may cause greater susceptibility to disease through malnutrition, access to health care, better housing and children’s and adult education.This study also provides recommendations how to reduce the prevalence of respiratory symptoms by improving households’ SES and/or poverty levels, one of the main risk factors for adverse health effects of respiratory symptoms in mothers and children from Tamil Nadu, South India. Since the quality of the domestic environment is very important, further intervention is needed to reduce respiratory symptoms in mothers and children, particularly young ones at a time when immune deviation usually occurs, regarding where they grow and spend most of their time. Finally, in order to reduce indoor air pollutants and respiratory symptoms in mothers and children, much more effort and greater attention needs to be paid to improve households’ low SES and/or poverty levels. The main goal should be sustainable development and poverty reduction that will enable people eventually to switch to clean fuels. SES was the most significant predicator of cooking fuel choice to ensure good health.

Метою роботи є розробка системи поточного контролю температури, вологості, атмосферного тиску повітря на основі сучасної мікроелектронної компонентної бази, а також моніторингу та аналізу стану забруднення повітря в частині визначення концентрації летючих органічних сполук (TVOC) і еквівалентного рівня діоксиду вуглецю (eCO2). Дипломна робота орієнтована на поглиблене вивчення фізичних методів визначення вмісту найбільших забрудників повітря та передбачає аналіз сучасного стану ринку електронних первинних перетворювачів в названій сфері та контролерів для побудови систем моніторингу та аналізу. В першому розділі дипломної роботи розглянуто нормативну базу в сфері отримання та аналізу інформації про поточний стан атмосферного повітря, проаналізовано відмінності в підходах до індексації якості повітря в Європі та Україні, визначено їх недоліки та переваги. У другому розділі розглянуто методики визначення вмісту основних забрудників повітря та проведено аналіз структурних схем аналізаторів, розглянуто особливості їх ключових конструктивних елементів, проведено порівняння конструкції і архітектури, наведено окремі принципові схеми вимірювання. В третьому розділі розглянуто сучасні типи мікроелектронних первинних перетворювачів фізичних параметрів атмосферного повітря, його хімічного складу та механічних забрудників. Проаналізовано технічні та метрологічні параметри сучасних сенсорних пристроїв з оглядом на відповідність сучасним вимогам, нормам, типам інтерфейсів. За результатами детального вивчення інформації у зазначених областях вибрано мікроелектронні сенсори з цифровим вихідним інтерфейсом для побудови мікроконтролерних системи моніторингу: - сенсор температури, вологості та атмосферного тиску BME 280; - мікромеханічний сенсор абсолютного тиску моделі BMP180 (висоти над рівнем моря) з роздільною здатністю 6 кПа ( відповідає роздільній здатності за зміною висоти 0.5 м) в режимі ультра-низького споживання та 2 hPa кПа ( відповідає зміні висоти 0.17 м) в режимі прецизійного вимірювання; - сенсор комплексного визначення якості повітря Adafruit CCS811 з можливістю визначення рівня летючих органічних сполук та ефективного рівня СО2 (CCS811 - Adafruit CCS811 Air Quality Sensor Breakout - VOC and eCO2) з додатковим вбудованим блоком прецизійного сенсора температури і вологості HDC1080. Для проектування системи моніторингу використано контролер ARDUINO UNO. В роботі запропоновано структурну схему системи і наведено схему підключення кожного з компонентів. Також у третьому розділі розроблено програмний код у програмному середовищі Arduino IDE для підключення окремих компонентів системи моніторингу до мікроконтролера, проведено його налаштування.
The work aim is an air quality system development for temperature, humidity, atmospheric pressure monitoring based on modern microelectronic components, as well as for monitoring and analysis of air pollution in terms of volatile organic compounds (TVOC) and equivalent levels of carbon dioxide and other pollutant gases concentration determination. Thesis is focused on in-depth study of physical methods for determining the the largest air pollutants content, on the electronic sensors current state analysis in this area and controllers choice for monitoring and analysis systems design. The first section of the thesis considers the regulatory framework in the field of obtaining and analyzing information about the atmospheric air current state, analyzes the differences in approaches to air quality indexing in the both Europe and Ukraine, identifies their disadvantages and advantages. The second section considers the methods of the major air pollutants content determining and analyzes the structural schemes of analyzers, considers the features of their key structural elements, compares the design and architecture, provides some basic electronic circuits. The third section considers modern types of atmospheric air physical parameters microelectronic sensors, its chemical composition and mechanical pollutants. The modern sensor technical and metrological parameters are analyzed with regard to compliance with modern requirements, norms, types of interfaces. Based on the results of a detailed study of information in these areas, modern microelectronic sensors with a digital output interface were selected to build microcontroller monitoring systems: - BME280 temperature, humidity and atmospheric pressure sensor; - micromechanical absolute pressure sensor model BMP180 (altitude) with a resolution of 6 kPa (corresponds to a change in altitude 0.5m) in the ultra-low consumption mode and 2 hPa kPa (corresponds to a change in altitude 0.17m) in the mode of precision measurement; - Adafruit CCS811 integrated air quality sensor with the ability to determine the level of volatile organic compounds and effective CO2 level (CCS811 - Adafruit CCS811 Air Quality Sensor Breakout - VOC and eCO2) with an additional built-in unit of precision temperature and humidity sensor HDC1080. The ARDUINO UNO controller was used to design the monitoring system. The structural scheme of the system is offered and the scheme of connection of each of components is resulted in the work. Also the program code in the Arduino IDE software environment for separate components of the monitoring system is developed, its adjustment is carried out.

碩士
弘光科技大學
職業安全與防災研究所
96
Measurement of volatile organic chemicals (VOC), including carbonyls, is of interest as these chemicals are ubiquitous, and have environmental and health significance. This study aimed to develop a new analytical method to simultaneously monitor airborne carbonyls compounds and low-polarity VOC. Carbonyls are collected onto an adsorbent (Tenax TA, coated with a derivatization agent (pentafluorophenyl hydrazine, PFPH)) to form thermo-stable derivatives suitable for subsequent analysis by thermal-desorption and GC/MS, whereas VOC are collected onto Tenax TA that is packed in the same sampling tube, and analyzed by the same way as carbonyls. Six carbonyls (formaldehyde, acetaldehyde, benzaldehyde, acetone, methyl ethyl ketone and methyl isobutyl ketone) and five low-polarity VOC (benzene, toluene, ethylbenzene, xylenes and styrene) were evaluated following a standard test protocol. The calibration ranges from 30 to 200 ng per tube for most carbonyls and VOC, and 200 to 1000 ng per tube for formaldehyde. The analytical precisions were within 7%, while the collection efficiency, tested using a static sampling bag, were between 94~98%. PFPH-coated Tenax TA (for collecting carbonyls) needs to be placed in the front section of the tube, and Tenax TA in the back section (for collecting VOC). The method detection limits for the current method range between 0.2~25ng per tube. Samples are stable for at least 10 days under ambient conditions. The current was also tested in field and proved satisfactory. This method is simple, feasible and with satisfactory accuracy and precision, and thus can be used as a reference method to simultaneously monitor environmental carbonyls and low-polarity VOC.

Student Number: 9503012G Master of Science. School of Geography, Archaeology and Environmental Studies
A brown haze which builds-up over Cape Town under calm and cold weather conditions causes public concern. The brown haze is thought to be due to the gaseous and particulate emissions from the city, industries, traffic and townships in the Cape Town region. Volatile organic carbon (VOCs) compounds are an important component of the haze layer particularly because of their reactivity. VOCs play an important role in the carbon budget and radiation balance, regional oxidant balance, and in the distribution of ozone and other reactive gases, both at the regional and global scale. In this study the variation in ambient VOC concentrations during brown and non-brown haze days over Cape Town during July and August 2003 were characterised. Ambient air samples were collected in evacuated stainless steel canistes from the South African Weather Service (SAWS) research aircraft (Aerocommander, ZS-JRB) and later analysed by gas chromotography equipped with a flame ionisation detector (GC-FID). Benzene, toluene, ethylbenzene and xylene (BTEX) were the specific VOCs targeted for this study. Comparable meteorology data was also collected to determine the effects of wind field and atmospheric stability on BTEX concentrations.

Dissertação de Mestrado Integrado em Engenharia Química apresentada à Faculdade de Ciências e Tecnologia
O principal objetivo desta dissertação de mestrado foi incorporar nanotubos de carbono (CNTs) em aerogéis de sílica para obtenção de materiais compósitos com boas propriedades de adsorção. Metiltrimetoxissilano (MTMS) e (3-aminopropil) trimetoxissilano (APTMS) foram utilizados como precursores de sílica, os quais, em diferentes proporções molares e utilizando a metodologia sol-gel, levaram à formação de aerogéis compósitos de CNTs-sílica.O surfactante utilizado foi escolhido entre brometo de hexadeciltrimetilamónio (CTAB), dodecil sulfato de sódio (SDS) e polietilenoglicol (PEG). Quando a síntese foi realizada com PEG, não foi obtido um gel, no entanto, o uso dos outros dois surfactantes produziu monólitos que não apresentaram diferenças significativas nos valores da massa volúmica bulk. Em relação ao tempo de gelificação, o CTAB apresentou os melhores resultados, com menor tempo de gelificação, o que é favorável para evitar a sedimentação dos CNTs na suspensão.O próximo parâmetro estudado foi o método de agitação e, embora a agitação mecânica proporcionasse menor massa volúmica bulk, o banho de ultrassom permitiu uma melhor dispersão dos CNTs na solução. Um estudo sobre a necessidade de uma etapa de lavagem para remover o surfactante dos géis foi também realizado. Comparando os resultados para a mesma formulação, com e sem lavagem, foi possível concluir que esta etapa foi fundamental, permitindo uma melhoria significativa na massa volúmica bulk, levando a uma redução de 5 a 10 kg m-3. A análise termogravimétrica confirmou que a etapa de lavagem removeu praticamente todo o surfactante da estrutura dos materiais.Os aerogéis com diferentes proporções de precursores (100% MTMS, 90% MTMS/10% APTMS e 80% MTMS/20% APTMS) foram caracterizados química, física e microestruturalmente. As amostras com 100% de MTMS apresentaram menores valores de massa volúmica bulk. A presença de grupos amina levou a um aumento em termos de tamanho dos poros, mas uma redução da área superficial específica. As técnicas de microscopia permitiram a visualização da microestrutura dos materiais, sendo visíveis grandes partículas secundárias, além de ser possível verificar a matriz de sílica à volta dos CNTs.Os testes de adsorção revelaram que a presença de CNTs levou a uma ligeira melhoria nas propriedades de adsorção dos adsorventes. Em relação aos compostos orgânicos voláteis (VOC), para os melhores materiais, com xileno e benzeno, foram obtidos elevadas percentagens de remoção (para benzeno superior a 80% e para xileno maior que 90%), enquanto para fenol foi removido apenas no máximo 30%. Para os fármacos, os melhores resultados foram obtidos para o naproxeno, com percentagens de remoção de até 96,9%, enquanto para a amoxicilina o melhor resultado de remoção foi em torno de 67%. Num estudo mais aprofundado do processo de adsorção, foi possível concluir que a presença de CNTs melhorou os parâmetros cinéticos (maior velocidade de adsorção), assim como os parâmetros das isotérmicas (maior afinidade entre a fase líquida e a fase sólida).
The main goal of this master’s dissertation was to incorporate carbon nanotubes (CNTs) in silica aerogels with the aim of obtaining composites with good adsorption properties. Methyltrimethoxysilane (MTMS) and (3-aminopropyl) trimethoxysilane (APTMS) were used as silica precursors, which, in different molar proportions and using the sol-gel methodology, led to the formation of CNTs-silica aerogel composites. The used surfactant was chosen among hexadecyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and polyethylene glycol (PEG). When the synthesis was performed with PEG, the gelation did not occur, however, the use of the other two surfactants produced aerogel monoliths that did not show significant differences in the values of bulk densities. Regarding the gelation time, CTAB showed the best results, with lower time, which is favorable to avoid CNTs sedimentation in the suspension. The next studied parameter was the agitation method and, even though the mechanical stirring provided lower bulk density, the ultrasound bath allowed a better CNTs dispersion in the solution. A study concerning the need of a washing step to remove the surfactant was also accomplished. Comparing the results for the same formulation, with and without washing, it was possible to conclude that this step was crucial, and allowed a significant improvement in the bulk density, leading to a decrease of 5 to 10 kg m-3. The thermogravimetric analysis confirmed that the washing step removed practically all the surfactant from the materials structure.The aerogels with different molar ratio of precursors (100% MTMS, 90% MTMS/10% APTMS and 80% MTMS/20% APTMS) were characterized chemical, physical and microstructurally. The samples with 100% MTMS presented lower values of bulk density. The presence of amine groups led to an increase in terms of pore size and a reduction regarding the specific surface area. The microscopy techniques allowed the visualization of the materials microstructure, showing large secondary particles, besides enabling the verification of the silica matrix around the CNTs. The adsorption tests revealed that the presence of CNTs led to a slight improvement in the adsorption properties of the adsorbents. Regarding volatile organic compounds (VOC), for the best materials, with xylene and benzene, high removal percentage rates were obtained (for benzene superior to 80% and for xylene higher than 90%), while for phenol a maximum of 30% was removed. For the pharmaceuticals, the best results were obtained for naproxen, with removal rates of up to 96.9 %, while for amoxicillin the best result was around 67% of removal. In a more in-depth study of the adsorption process, it was possible to conclude that the presence of CNTs improved the kinetic parameters (higher adsorption velocity), as well as the parameters of the adsorption isotherms (higher affinity between liquid phase and solid phase).

Volatile organic compounds (VOCs) in air and heavy metal ions, anions, microorganism in water are environmental contaminants that require detection at certain low concentrations to avoid detrimental effects. Analytical instruments can accurately determine the concentration and composition of the contaminants at trace levels. However, these methods require skilled personnel to operate. Hence sensors should have fast response, low maintenance and easy to handle. In the present work, environmental monitoring sensor for volatile organic compounds, anion and E. coli was developed. The sensor is resistive sensor architecture with organic nanocomposite as sensing layer. The conjugated organic molecule with receptor moieties that can interact and exhibit affinity to each of the analyte was designed and synthesized. A new conducting polymer for sensing toluene, aldehyde is designed and fabricated. The sensor shows highest sensitivity and selectivity for targeted analyte. The sensor response is explained by molecular dynamics simulation. The solubility parameter of the new polymers is calculated by molecular dynamics and is used for elucidation of rationale of the mechanism for selectivity. The interaction energy of the sensing layer calculated by simulation is higher for targeted analyte than that for other analytes. The adsorption of vapors on the sensing layer results in volumetric change of the sensing layer. The effect can be experimentally determined by monitoring the thickness of the film and the change in the parameters such as mass change, capacitance, resistance change, refractive index change that occurs due to absorption of vapors in the polymers. Here, laser Doppler vibrometry, a non contact method is used to measure the displacement occurring due to interaction of a new polymer film with analyte vapors. A sensor for real time monitoring of nitrate ion concentration in water is fabricated. A new conjugated polymer is designed for selection of nitrate is used as a sensing molecule. The sensor is tested for various concentrations of nitrate ions and possible interferents effect. An organic nanocomposite based resistive sensor is designed and fabricated to detect E. coli in water. The organic molecule with receptor groups was selected such that receptor group would interact and exhibit affinity to the functional groups present on outer membrane of the cell wall of the E. coli. The resistance change is caused due to interaction and is because of E. coli acting as p-dopant to sensor molecule. The electrostatic interaction between positively charged amine groups on sensor molecule and negatively charged E. coli is believed to be the interaction mechanism. This work demonstrates that the conjugated molecules with suitable moieties can bind with analyte like VOCs, heavy metal ions, anions, microorganism, that can be used as sensing element in resistive sensor architecture.