Dissertations / Theses on the topic 'BTEX in air. Validación'

Orientador: Reginaldo Guirardello<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica<br>Made available in DSpace on 2018-08-03T22:33:18Z (GMT). No. of bitstreams: 1 Silva_ConsueloCristinaGomes_M.pdf: 1700273 bytes, checksum: 223e8e7c5d3ede67496010e0d1185395 (MD5) Previous issue date: 2004<br>Resumo: Com a busca constante pelo Desenvolvimento Sustentável, os órgãos ambientais estão demandando uma maior atenção à contaminação de recursos hídricos, provenientes de águas residuárias. As águas residuárias podem ser provenientes de descartes domésticos, industriais ou ainda pluviais. Os compostos químicos causam danos à saúde e ao equilíbrio dos ecossistemas. Um caso particular e de interesse é o caso do BTEX (Benzeno, Tolueno, Etilbenzeno e os Xilenos), pois, estes compostos são solventes de uso industrial comum e são tóxicos à saúde humana, além de inviabilizarem a exploração de aqüíferos por eles contaminados. Nesta pesquisa, apresentamos uma configuração otimizada em termos de consumo energético e custo fixo para uma unidade de Air Stripping respeitando as restrições ambientais e operacionais, descrevendo e efetuando o projeto ótimo da unidade para a remoção de BTEX presente em águas residuárias, apresentando uma metodologia para elaboração de projetos de sistemas de tratamento, dimensionando bombas e sopradores, elaborando um projeto de colunas de pratos perfurados e estimando custos em plantas químicas. O modelo considerado nesta pesquisa foi desenvolvido por ALBUQUERQUE (2002). Para a simulação da unidade de Air Stripping, usamos o pacote computacional GAMS (General Algebric Modeling System), que é designado à construção e solução de modelos grandes e complexos de programação matemática. Para a otimização da unidade, trabalhamos com Programação Não Linear e Programação Mista Inteira Não - Linear, a fim de minimizar o impacto resultante do lançamento destes poluentes e sua dispersão no meio ambiente. Os resultados indicam a remoção dos contaminantes em grau satisfatório para a unidade, além de atingirem os objetivos propostos<br>Abstract: With the constant search for the Sustainable Development, the ambient agencies are demanding bigger attention to contamination of resources hídricos, proceeding from residuary waters. The residuary waters can be proceeding from domestic, industrial or still pluvial discardings. Chemicals cause damages to the health and to the balance of ecosystems. A particular case of interest is the case of BTEX (Benzene, Toluene, Etilbenzene and the Xilenes), which are solvents of common industrial use and are toxic to the health human being, besides making impracticable the exploration of water-bearing or contaminated by them. In this research we present an optimal configuration in terms of energy consumption and fixed cost for a unit of Air Stripping, describing and effecting the excellent project of the unit for the present removal of BTEX in residuary waters, presenting a methodology for elaboration of projects of treatment systems, design bombs and puffers, elaborating a project of perforateed plate columns and estimating costs in chemical plants.The model considered in this research was developed by ALBUQUERQUE (2002). For the simulation of the unit of Air Stripping we use computational package GAMS (General Algebric Modeling System) that it is assigned to the construction and solution a complex models of mathematical programming. For the optimization of the unit we work with Non Linear Programming and Integer Mixed Non Linear Programming, in order to minimize the resultant impact of the launching of these pollutants and its dispersion in the environment. The results indicate remova I of the contaminates in satisfactory degree for the unit, besides reaching the objectives proposed in this work<br>Mestrado<br>Desenvolvimento de Processos Químicos<br>Mestre em Engenharia Química

La qualité de l’air extérieur (QAE) a fait l’objet d’une législation dès 1996 avec la loi LAURE. Depuis 2008, la directive européenne 2008/50/CE a instauré des obligations de mesure et de seuils à ne pas dépasser pour certains polluants à l’échelle européenne. Selon de nombreuses données toxicologiques et épidémiologiques, la pollution de l’air est à l’origine d’insuffisances respiratoires, d’asthme, de maladies cardiovasculaires et de cancers.Les composés organiques volatils (COV) et notamment le benzène, le toluène, l’ethylbenzène et les xylènes (les composés BTEX) sont des polluants avérés et participent grandement à la dégradation de la qualité de l’air intérieur et extérieur. Ce travail de thèse a concerné la réalisation d’un multicapteur de gaz à base d’oxyde métallique pour la détection de traces de BTEX dans le cadre du projet SMARTY (SMart AiR qualiTY). Un système de caractérisation électrique complet a été conçu et mise au point pour la détection de très faibles concentrations de BTEX (le ppb). Après une étude bibliographique, plusieurs matériaux ont été sélectionnés (WO3, ZnO, SnO2). Les caractérisations électriques des couches sensibles sélectionnées ont été effectuées sous air sec et sous différents taux d’humidité en présence de BTEX et de gaz interférents (NO2, CO2). Le WO3 a montré les meilleures performances en présence d’humidité et a été choisi pour le transfert de technologie qui accompagne les nouveaux transducteurs brevetés AMU. Le multicapteur à base de WO3 a montré une détection limite de 1 ppb sous 50% d’humidité relative et a permis de détecter et de quantifier de manière efficace les BTEX<br>Outdoor air quality is subjected to the law LAURE since 1996. In 2008, the european directive 2008/50/EC introduced measurement requirements and thresholds that should not be exceeded for certain pollutants on a european scale. According to several toxicological and epidemiological studies, air pollution causes respiratory failure, asthma, cardiovascular diseases and cancers. In Europe, air pollution is responsible for more than 300 000 early deaths a year.Volatile organic compounds (VOCs), particularly benzene, toluene, ethylbenzene and xylenes (BTEX compounds) are proven pollutants and play a major role in the degradation of indoor and outdoor air quality. This thesis is dedicated to the development of a metal oxide based multi-gas sensor for the detection of traces of BTEX within the framework of the SMARTY project (SMart AiR qualiTY). A complete electrical characterization system was designed and implemented for the detection of sub-ppm concentrations of BTEX.Based on the state-of-art, several materials were selected (WO3, ZnO, SnO2). The electrical characterizations of the selected sensitive layers were carried out under dry air and under different humidity levels in the presence of BTEX and interfering gases (NO2, CO2). Tungsten oxide (WO3) exhibits the best performance in the presence of moisture and is chosen for the technology transfer that accompanies the new patented AMU transducers. The WO3-based multi-sensor has a lower limit of detection (LOD) of 1 ppb at 50% relative humidity and effectively detects and quantifies BTEX

U okviru doktorske disertacije opisane su jedinstvene fiziĉko-hemijske karakteristikegrupe supstanci benzena, toluena, etilbenzena i ksilena koje pripadaju istraživanjimanajnovijeg trenda nauĉne javnosti. Posebno su opisane perzistencija ipseudoperzistencija, transport, distribucija i negativan i toksiĉan uticaj na zdravljeĉoveka i životnu sredinu. Sprovedena su eksperimentalna istraživanja zavisnostikoncentracionih nivoa BTEX jedinjenja u izduvnim gasovima i operativnih parametaraeksperimentalnog motora SUS. Na osnovu dobijenih rezultata eksperimentalnihistraživanja definisan je emisioni model BTEX jedinjenja simulacijom kretanjaputniĉkog automobila Fiat Punto Classic u skladu sa NEDC ciklusom koji naodgovarajući naĉin reprezentuje standarde uslove vožnje u evropskim gradovima.<br>In this thesis, the unique physicochemical characteristics of a group of substancesconsisting of benzene, toluene, ethylbenzene and xylene have been described.Special emphasis has been placed on their characteristics of persistence and pseudopersistence,transport, distribution and the negative and toxic influence on humanhealth and the environment. The experimental research of the interdependence of theconcentration levels of BTEX compounds in the exhaust gases and the operationalparameters of the experimental IC engine has been conducted. Based on theexperimental research results, the emission model of the BTEX compounds has beendefined by a simulation of movement of a Fiat Punto Classic passenger car inaccordance with the NEDC cycle, which appropriately represents the standard drivingconditions in European cities. Research conducted within the thesis represents thenewest trend of investigation in the scientific world.

La qualité de l’air extérieur (QAE) a fait l’objet d’une législation dès 1996 avec la loi LAURE. Depuis 2008, la directive européenne 2008/50/CE a instauré des obligations de mesure et de seuils à ne pas dépasser pour certains polluants à l’échelle européenne. Selon de nombreuses données toxicologiques et épidémiologiques, la pollution de l’air est à l’origine d’insuffisances respiratoires, d’asthme, de maladies cardiovasculaires et de cancers.Les composés organiques volatils (COV) et notamment le benzène, le toluène, l’ethylbenzène et les xylènes (les composés BTEX) sont des polluants avérés et participent grandement à la dégradation de la qualité de l’air intérieur et extérieur. Ce travail de thèse a concerné la réalisation d’un multicapteur de gaz à base d’oxyde métallique pour la détection de traces de BTEX dans le cadre du projet SMARTY (SMart AiR qualiTY). Un système de caractérisation électrique complet a été conçu et mise au point pour la détection de très faibles concentrations de BTEX (le ppb). Après une étude bibliographique, plusieurs matériaux ont été sélectionnés (WO3, ZnO, SnO2). Les caractérisations électriques des couches sensibles sélectionnées ont été effectuées sous air sec et sous différents taux d’humidité en présence de BTEX et de gaz interférents (NO2, CO2). Le WO3 a montré les meilleures performances en présence d’humidité et a été choisi pour le transfert de technologie qui accompagne les nouveaux transducteurs brevetés AMU. Le multicapteur à base de WO3 a montré une détection limite de 1 ppb sous 50% d’humidité relative et a permis de détecter et de quantifier de manière efficace les BTEX<br>Outdoor air quality is subjected to the law LAURE since 1996. In 2008, the european directive 2008/50/EC introduced measurement requirements and thresholds that should not be exceeded for certain pollutants on a european scale. According to several toxicological and epidemiological studies, air pollution causes respiratory failure, asthma, cardiovascular diseases and cancers. In Europe, air pollution is responsible for more than 300 000 early deaths a year.Volatile organic compounds (VOCs), particularly benzene, toluene, ethylbenzene and xylenes (BTEX compounds) are proven pollutants and play a major role in the degradation of indoor and outdoor air quality. This thesis is dedicated to the development of a metal oxide based multi-gas sensor for the detection of traces of BTEX within the framework of the SMARTY project (SMart AiR qualiTY). A complete electrical characterization system was designed and implemented for the detection of sub-ppm concentrations of BTEX.Based on the state-of-art, several materials were selected (WO3, ZnO, SnO2). The electrical characterizations of the selected sensitive layers were carried out under dry air and under different humidity levels in the presence of BTEX and interfering gases (NO2, CO2). Tungsten oxide (WO3) exhibits the best performance in the presence of moisture and is chosen for the technology transfer that accompanies the new patented AMU transducers. The WO3-based multi-sensor has a lower limit of detection (LOD) of 1 ppb at 50% relative humidity and effectively detects and quantifies BTEX

Muitos dos locais onde as atividades são realizadas nas academias de ginásticas são salas pequenas e fechadas com sistema de climatização artificial, freqüentados por um grande número de alunos realizando seus exercícios e profissionais auxiliando as atividades. Com isso, há uma intensa transpiração desses indivíduos, uma freqüente rotina de limpeza do piso e de equipamentos com pequenos intervalos, possibilitando a alterações da qualidade do ar indoor. O presente trabalho busca mostrar as tendências de variações nos valores das concentrações dos poluentes atmosféricos BTEX em ambiente indoor, especificamente na sala de spinning de uma academia de ginástica do Rio de Janeiro. Para o monitoramento da qualidade do ar foram utilizados cartuchos de carvão ativado SKC, acoplado a uma bomba KNF com vazão de 1l min. Para a extração de cada amostra foi feita a análise cromatográfica com cromatógrafo a gás modelo 6890 acoplado a um espectrômetro de massa modelo 5973 da marca Agilent. Foram analisadas 34 amostras coletadas na salas de spinning durante as aulas com atividades aeróbicas, o que intensificava a respiração dos indivíduos, possibilitando uma maior inalação destes COVs. Em contrapartida, também foram coletadas 5 amostras outdoor, 4 delas pareadas indoor/ outdoor para uma análise comparativa das concentrações destes poluentes. Dentre os compostos orgânicos voláteis analisados, o tolueno é o BTEX mais abundante obtido neste trabalho, representando 81% destes COVs indoor. Todas as amostras medidas em pares indoor/ outdoor tiveram concentrações maiores no interior, exceto para o benzeno no dia 3/12/2010. Simples atividades usualmente realizadas pelo homem, como a inserção de piso emborrachado, manutenção do sistema de climatização artificial, e limpeza podem alterar o ar indoor. As conclusões alcançadas após as medições das concentrações de BTEX foram de que o ar indoor estava mais poluído do que o outdoor. Este monitoramento da qualidade do ar indoor ainda é escasso no Brasil. Alguns esforços tem sido feito em relação a ambientes confinados como a Portaria n&#730;3523 do Ministério da Saúde, regulamentando o controle dos ambientes climatizados e a Resolução n&#730;9 da Agência Nacional de Vigilância Sanitária, além da Resolução CONAMA n &#730;3 estabelecendo padrões de qualidade do ar para alguns compostos químicos, porém muitos compostos químicos ainda não são legislados ou não possuem a devida atenção, não sendo suficientes para contemplar a complexidade do assunto<br>In many gyms work-out activities take place in small enclosed rooms where the climate is controlled artificially. Normally, those rooms are full of students doing their workout and trainers helping them. Intense human transpiration requires a frequent floor and equipment cleaning routine. This routine, performed at short intervals can affect the indoor air quality. This study is aimed at showing varying concentration levels of the BTEX air pollutant at a gym in Rio de Janeiro, Brazil, specifically the spinning room. To monitor the air quality, activated charcoal cartridges (SKC) were used, coupled to a KNF pump with a flow rate of 1l min. For the extraction of each sample, a gas chromatographic analysis machine model 6890 was used coupled to an Agilent mass spectrometer model 5973. We analyzed a total of 34 air samples collected in the spinning room during active aerobic classes; the increased respiration from the subjects allow for a greater inhalation of VOCs. In Contrast, five samples were also collected outdoors; four of them were paired indoor / outdoor for comparative analysis of these pollutants. Among the volatile organic compounds analyzed, toluene was the most abundant BTEX found in this study, representing 81% of indoor VOCs. In all the indoor / outdoor paired samples, the concentration was higher in the interior samples, with one exception, benzene on 3/12/2010. Simple changes that can easily be done by man, such as the installation of rubberized flooring, regular maintenance of the air acclimatization equipment, and general cleanliness can greatly affect the indoor air quality. The conclusion achieved after looking at the BTEX measurements was that the indoor air was more polluted than the air outdoors. This air quality monitoring is still scarce in Brazil. Some efforts have been made in relation to confined spaces such as Ordinance n&#730; 3523 from the Ministry of Health, which regulates the air of air-conditioned environments and Resolution n&#730; 9 of the National Agency for Sanitary Vigilance, as well as Resolution CONAMA n&#730; 3 by setting standards for air quality for some chemical compounds, unfortunately many chemical compounds are not yet legislated or receive proper attention in this matter, therefore not giving this indoor air pollution matter enough grounds to address the complexity of the subject

Le principe des echantillonneurs diffusifs repose sur la diffusion des composes organiques volatils, regie par la premiere loi de fick, jusqu'a un adsorbant sur lequel ils sont pieges. Ces appareils sont de plus en plus utilises pour controler les atmospheres de travail, mais on connait tres peu leurs capacites en milieu peu pollue. Il s'agit donc d'une etude menee sur des echantillonneurs de type tube pour les btex en les testant et en les etalonnant a tres basses concentrations (ppbv) dans des chambres de simulation, dans differentes conditions (humidite, agitation atmospherique), et si besoin en les modifiant (changement de la phase d'adsorption). Les durees d'exposition ont varie de une heure a cinq jours. Les etalonnages ont ete effectues a partir de la determination des concentrations par un echantillonnage dynamique des atmospheres. Nous avons d'abord tester le tenax ta comme adsorbant, et avons montre que les vitesses d'enrichissement des composes les plus volatils tels que l'hexane et le benzene n'etaient pas lineaires. Nous avons pu expliquer ces phenomenes par la difference de volatilite et par l'equilibre entre les composes et l'adsorbant. Pour etudier ces phenomenes, nous avons teste un deuxieme adsorbant, le carbopack b. Celui ci possede une plus grande affinite pour les composes etudies. En effet, nous obtenons a doses d'exposition egales un enrichissement legerement plus important sur le carbopack b, mais nous avons conserve cette non-linearite. Cette derniere n'empeche pas l'utilisation de ces echantillonneurs : on peut tracer une courbe de tendance d'enrichissement, et s'y referer pour calculer la concentration moyenne a laquelle l'echantillonneur a ete expose. L'utilisation de ces echantillonneurs a ete validee par des campagnes de prelevements en milieu urbain avec des comparaisons entre prelevements dynamiques et diffusifs. Pour les composes aldehydiques un echantillonneur de type badge a ete cree. Dans ce dernier cas, le milieu adsorbant est un filtre impregne de 2,4 dinitrophenylhydrazine. Cet echantillonneur a ete calibre en suivant le meme protocole que celui etabli auparavant. Afin d'etudier les parametres qui influent sur ces prelevements diffusifs, nous avons fait varier le nombre de filtres dans un echantillonneur, ainsi que la porosite des filtres. Nous avons ainsi pu ameliorer la limite de detection et la quantitativite par rapport aux echantillonneurs commercialises. L'utilisation de ces echantillonneurs a ete validee par des mesures en atmosphere faiblement concentree.

Les BTEX est une famille de polluants très répandue en air intérieur. Ils présentent des effets nocifs sur la santé humaine à des faibles concentrations ce qui a emmené le législateur à fixer des seuils afin de limiter l'exposition des gens. L'objectif de ce travail de recherche est de développer et de mettre en place une méthode analytique sensible, précise et rapide basée sur un dispositif de mesure. Le dispositif ainsi mis en place est un chromatographe en phase gazeuse miniaturisé équipé d'un mini détecteur à photo ionisation dédié à la détection des BTEX en temps quasi-réel. Le système analytique est très portable ayant une consommation gazeuse très faible assurant une autonomie élevée sur de longues durées. Son mode de fonctionnement se base sur l'échantillonnage de l'air dans une boucle connecté à une vanne six voies. L'injection de l'échantillon sur une colonne analytique placée dans un four pour la séparation est assurée par le changement de la position de la vanne avant la détection par photo ionisation. Le nouveau dispositif miniaturisé a été déployé lors de deux campagnes intensives menées dans un collège énergétiquement performant. Cette étude a porté sur la surveillance temporelle de la concentration des polluants présents en air intérieur, y compris les BTEX. Les résultats ainsi obtenus pour les BTEX avec notre dispositif ont été comparés à ceux fournis par d'autres techniques dites techniques de référence. Ces campagnes de terrain ont permis donc de valider les performances analytiques, la robustesse et l'autonomie de cette nouvelle méthodologie<br>BTEX are very widespread indoor air pollutants. Their harmful effects on human health had led the legislator to set thresholds in order to limit the population exposure. The aim of this thesis is to develop a sensitive, accurate and fast analytical method based on a measurement device. Therefore, the device implemented is a miniaturized gas chromatography (GC) equipped with a mini photo ionization detector dedicated to BTEX detection in indoor air in near-real time. The miniaturized GC is very portable with a very low gas consumption which enhances its autonomy over a long period. Its operation mode is based on air sampling inside a sample loop which is connected to a six port valve. The injection over a heated analytical column is ensured by switching the valve position before detection by a photo ionization detector. This novel device was used in real conditions during two field campaigns conducted in an energy efficient college. This study focused on the temporal monitoring of indoor air pollutant concentrations including BTEX. The results obtained with our miniaturized device for BTEX were compared to those given by other techniques known as reference techniques. These field campaigns have therefore enabled us to validate the analytical performances, the robustness and the autonomy of this novel analytical method

Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2014-10-29T22:11:50Z No. of bitstreams: 1 TESE_GIL.pdf: 2275297 bytes, checksum: 45e4c2a7be1a4d3eeb37b526cabd2cae (MD5)<br>Approved for entry into archive by Ana Hilda Fonseca (anahilda@ufba.br) on 2014-10-30T02:23:20Z (GMT) No. of bitstreams: 1 TESE_GIL.pdf: 2275297 bytes, checksum: 45e4c2a7be1a4d3eeb37b526cabd2cae (MD5)<br>Made available in DSpace on 2014-10-30T02:23:20Z (GMT). No. of bitstreams: 1 TESE_GIL.pdf: 2275297 bytes, checksum: 45e4c2a7be1a4d3eeb37b526cabd2cae (MD5)<br>CNPq<br>A poluição atmosférica é, dentre os diversos tipos de poluição, a que mais tem causado incômodo a população com implicações à saúde, originando desde simples irritações até o desenvolvimento de câncer. A concentração de alguns poluentes do ar em ambientes ocupacionais pode ser muitas vezes, superior aos valores estabelecidos por lei, devido à localização de fontes potenciais de emissão e pela ausência de sistemas de ventilação adequados. A princípio, o objetivo deste trabalho foi fazer uma pesquisa exploratória de caráter quantitativo/qualitativo com trabalhadores de postos de combustíveis de cidades do Recôncavo Sul da Bahia e realizar uma reflexão crítica sobre suas percepções sobre os efeitos à saúde causados pelos compostos orgânicos voláteis (COV) durante suas atividades laborais. Após essa análise inicial, foi desenvolvido um método analítico para determinação das concentrações de BTEX (benzeno, tolueno, etilbenzeno e xilenos) em amostras de ar ambiente de postos de combustíveis por amostragem ativa em tubos adsorventes contendo carvão ativo, seguido de dessorção química e análise por cromatografia a gás com detector de ionização em chama (CG/DIC). Foram realizados testes com diversos solventes a fim de se verificar a taxa de recuperação (TR) de cada um deles. Os testes revelaram que o diclorometano (CH2Cl2) apresentou os melhores resultados de TR, com valores acima de 75% de extração dos compostos BTEX. Os parâmetros analíticos utilizados para validação do método cromatográfico foram: seletividade, linearidade, precisão, exatidão, limite de detecção e limite de quantificação. A amostragem foi realizada em ar ambiente dos postos de combustíveis da cidade de Amargosa, Bahia. As concentrações encontradas no ar ambiente dos postos de combustíveis variaram de 16,9 a 44,5 μg m-3 para o benzeno; de 39,9 a 247 μg m-3 para o tolueno; de 15,6 a 29,4 μg m-3 para o etilbenzeno; de 12,7 a 68,5 μg m-3 para o m-xileno; de 13,7 a 63,3 μg m-3 para o pxileno e de 13,1 a 42.2 μg m-3 para o o-xileno. Os resultados obtidos pelo método proposto foram comparados com os resultados obtidos por um método usando dessorção térmica e não apresentou diferenças significativas para a faixa de concentração estudada, ratificando a validade do método. As concentrações dos compostos encontrados neste trabalho são consideradas pela NR-15 do Ministério do Trabalho e Emprego, com exceção do benzeno, como não cancerígeno para seres humanos. Segundo estudo realizado pela Organização Munidal da Saúde (OMS), os níveis de benzeno encontrados são classificados como possíveis causadores de câncer devido seu caráter cumulativo durante o tempo de vida laboral de um trabalhador nesses ambientes.<br>Air pollution is the type of pollution that has caused more discomfort for the population. This type of pollution has caused damage to human health resulting from simple irritations to the development of cancer. Many times, the concentration of some air pollutants in occupational environments can be greater than the values established by law due to the location of potential emission sources and the default of adequate ventilation systems. First, this work aimed to develop an exploratory quantitative/qualitative research with gas station attendants in cities located in the Southern Recôncavo of Bahia and promoting a critical reflection on their perceptions about the effects on human health caused by volatile organic compounds (VOC) during their work activities. After this initial analysis, an analytical method was developed to determination of BTEX (benzene, toluene, ethylbenzene and xylenes) concentrations in samples of ambient air of gas stations by active sampling on adsorbent tubes containing activated charcoal followed by chemical desorption and analysis by gas chromatography with flame ionization detector (GC/FID). Tests were done using various solvents in order to verify the recovery rate (RR) of each one of them. So, tests indicated that dichloromethane (CH2Cl2) presented the best results of RR, with values above 75% of extraction of BTEX compounds. The selectivity, linearity, precision, accuracy and detection and quantification limits of the chromatographic method were validated. Sampling was performed in ambient air of gas stations located in Amargosa city in Bahia. The concentrations found in ambient air of gas stations ranged from 16.9 to 44.5 μg m-3 for benzene; 39.9 to 247 μg m-3 for toluene; 15.6 to 29.4 μg m-3 for ethylbenzene; 12.7 to 68.5 μg m-3 for m-xylene; 13.7 to 63.3 μg m-3 for p-xylene and 13.1 to 42.2 μg m-3 for o-xylene. The results obtained in this proposed method were compared with the results obtained in a method using thermal desorption and showed no significant differences for the studied analytical range, confirming the validity of the method. The concentrations of the compounds found in this study are classified not carcinogenic to humans by NR- 15 from the Ministério do Trabalho e Emprego, with the exception of Benzene. According to a study developed by the World Health Organization (WHO), the levels of Benzene found are classified as possible causes of cancer because of its cumulative feature during the work lifetime of a gas station attendant in those environments.

Les precipitations jouent le role de vecteur de la pollution, en transportant les especes chimiques de la phase gazeuse jusqu'au sol. Il est donc important de determiner la capacite d'incorporation de ces composes dans la pluie en etudiant les phenomenes de transfert dans les gouttes. Notre interet s'est principalement porte sur les btex (benzene, toluene, ethylbenzene, m-xylene et o-xylene), principaux composes aromatiques emis sur les sites urbains. Pour cette etude, nous avons mis au point une technique d'analyse nous permettant de gerer la mesure des btex dans l'eau. La micro extraction en phase solide (spme) permet d'atteindre des limites de detection de l'ordre de 80 ng. L#-#1 lorsque les solutions aqueuses sont dopees avec nacl. L'etude phenomenologique des echanges gaz-liquide a ete realisee dans un reacteur monogoutte, construit specifiquement pour cette etude. Il permet le controle des parametres de gouttes (taille et composition), ainsi que la concentration en btex dans la phase gazeuse. Nous avons montre que les masses de btex incorporees dans les gouttes sont nettement superieures a celles predites par la loi de henry et les concentrations en phase gazeuse. Le rapport de lessivage augmente lorsque la taille de la goutte diminue. Le phenomene d'incorporation implique, dans nos conditions experimentales, essentiellement deux etapes: le transport en phase gazeuse et le franchissement de l'interface. Ce dernier, caracterise par la mesure du coefficient d'accommodation massique, constitue l'etape limitante au transfert, etape d'autant plus limitante que le diametre de la goutte est grand. Ce travail de simulation nous a ensuite permis de comprendre et de justifier les resultats obtenus lors de campagnes de mesures sur un site reel: l'agglomeration grenobloise. Les quantites de btex dans les gouttes augmentent lorsque la temperature ou l'intensite de la pluie diminue

The objectives of this study are to measure the non-methane volatile organic carbon (NMVOC&#039<br>s) emissions from passenger cars in Turkey having gasoline engines, to determine emission factors of these vehicles for BTEX compounds and comparison of emission factors obtained in this study with the emission factors of the other countries. This study was conducted in two parts: The first part was to determine the categories of passenger cars widely used in Turkey, and also to determine the average carbon monoxide (CO) and hydrocarbon (HC) emissions at idle condition for these car types based on the exhaust emission measurements of Ankara &Ccedil<br>evre Koruma Vakfi (AN&Ccedil<br>EVA). The second part of the study was to analyze the gas composition of exhaust gasses at different road conditions for BTEX components by using gas chromatography. The results of the study have shown that the cars named under &lsquo<br>&lsquo<br>Tofas&rsquo<br>&rsquo<br>constitute 31.5% and &lsquo<br>&lsquo<br>Fiat&rsquo<br>&rsquo<br>13.1% of the total cars in Turkey and they are manufactured by the same company. Therefore, studies have been performed with &lsquo<br>&lsquo<br>Tofas/Fiat&rsquo<br>&rsquo<br>cars. The highest emission factors among hydrocarbons investigated in this study were found for toluene and m-xylene. Generally, as driving speed increases the emissions of HC&rsquo<br>s are found to decrease in concentration. It was interesting to note that the highest emissions occur at 30 km/hr speed which is the mostly used speed in crowded streets and busy intersections. Therefore, it was concluded that it is very important to take measures for emissions in the city traffic. Cold start emissions were also found to be higher than the hot start emissions.

碩士<br>國立中山大學<br>環境工程研究所<br>92<br>In this field-scale study, air sparging (AS) system was applied at a petroleum-hydrocarbon spill site to remediate contaminated soil and groundwater in situ. The objective of this study was to evaluate the effectiveness of the AS system on volatile organic compounds (VOC) removal via the volatilization mechanism. Moreover, the AS system would also enhance the in situ bioremediation process due to the increased oxygen concentration in the subsurface. Results from the preliminary site characterization show that high concentrations of benzene and toluene were present in the subsurface in the western part of the site. Up to 15.62 and 30,957 mg/Kg of benzene and toluene were detected in soil samples, respectively. Moreover, up to 0.068 and 4.8 mg/L of benzene and toluene were observed in groundwater samples, respectively. The following remediation activities were conducted during the one-year investigation and remediation period: 1. Construction of four recovery wells were for light non-aqueous phase liquid (LNAPL) and contaminated groundwater extraction to prevent the expansion of VOC plume. The extracted groundwater was delivered to the wastewater treatment plant for treatment before discharge. 2. Installation of ten air sparging wells to enhance the removal of VOC through volatilization and biodegradation processes. 3. Conduction of (1) soil gas survey, (2) soil and groundwater sampling and analyses, and microbial enumeration periodically to evaluate the effectiveness of AS on VOC removal. Results from the field-scale study indicate that the AS system is able to effectively contain the plume. This can be confirmed by the following findings: (1) decrease in VOC concentrations in both soil and groundwater, (2) increase in carbon dioxide and increase in oxygen concentrations in the soil gas samples, and (3) increase in bacterial population in soil samples. Results from this study indicate that AS system can effectively contain the plume and manage this petroleum hydrocarbon spill site.

Prior studies have found that human exposure to hazardous air pollutants (HAPs) occurs in homes; however, the depth of these assessments was limited by the extent of the analyzed data. The present Ph.D. dissertation focused on air contaminants of concern in residential buildings, the possible sources of these pollutants, and population subgroups with greater contaminant risk. This research also evaluated the effects of building characteristics and household activity patterns on indoor pollution and risk levels. To this end, an in-depth analysis was performed of data from the Relationships of Indoor, Outdoor and Personal Air (RIOPA) study, one of the most comprehensive exposure assessments to date. Using personal concentrations from the RIOPA study, a cancer risk assessment was performed to identify both important pollutants and populations at higher risk. The analyzed compounds were acetaldehyde, benzene, chloroform, carbon tetrachloride, p-dichlorobenzene (p-DCB), ethylbenzene, formaldehyde, methylene chloride, methyl tert-butyl ether (MTBE), styrene, trichloroethylene and tetrachloroethylene. Results indicate that Hispanics and non-Hispanic whites had median cumulative cancer risks (CCR) of 520×10-6 and 440×10-6, respectively, for which the main contributors were formaldehyde, p-DCB, acetaldehyde, chloroform and benzene. Statistically significant differences in CCR between and within Hispanic and whites were primarily due to exposures to p-DCB. Exposure to formaldehyde was further investigated because this compound was the largest contributor to CCR for 69% of Hispanics and 88% of whites, and because most participants had similar cancer risks from these exposures (median = 260×10-6, coefficient of variance = 28%). Results suggest that the U.S. population may be experiencing chronic exposures because of long-term formaldehyde emissions from pressed-wood materials bound with urea-formaldehyde resins. Source removal may be the most effective way to decrease these chronic exposures. Benzene was also examined further because it is a known human carcinogen. Results show that indoor benzene concentrations increased as the proximity of parked vehicles decreased. Residing in a home with an attached garage could lead to exposures to benzene ten times higher than while commuting in a car in heavy traffic, and with mean excess cancers of 17×10-6. Detached garages could reduce health risks from exposure to benzene and other gasoline-related pollutants.<br>text

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, August 2015.<br>Petrol and diesel fumes are known to be anthropogenic sources of air pollutants that have a negative impact on both environmental and human health. In developing countries, attendants are still employed to pump fuel for customers. In South Africa gas pump attendants refuel vehicles with various octane unleaded petrol, lead replacement petrol (LRP) and diesel on a daily basis. Attendants are particularly at risk to adverse health effects associated with inhalation of hazardous air pollutants (HAPs). Of increasing concern in recent years are the volatile organic compounds (VOCs), with particular reference to the six aromatic hydrocarbons (benzene, toluene, ethyl benzene and three isomeric xylenes), namely the BTEX.

碩士<br>國立屏東科技大學<br>環境工程與科學系<br>93<br>The influence of both MTBE and BTEX emissions from vehicle and industrial sources on the ambient air nearby the residents’ area was investigated. The MTBE and BTEX samples were collected from the five different sites in southern Taiwan. Sampling sites included the industrial areas, traffic intersection sites, night market sites, parking lots and one motor vehicle repairing plants in southern Taiwan. Charcoal tubes (ORBO-32,100 mg/50 mg) were used to collect air stream, and the GC/FID technique was applied to quantify the concentrations of both MTBE and BTEX. Results showed in the industrial areas, both MTBE and BTEX concentrations at Lin-yuan and Ren-Wu had the highest concentration. At the traffic intersection sites, the concentrations of MTBE and BTEX were associated with the vehicle density. The highest concentration occurred at Minsheng’s intersection road. At the night market, the higher concentration occurred at Rui-Guan and Ping-Tung night market. At the parking lots, the lower concentration was at the C parking lot. For the motor vehicle repairing plant, the concentrations of MTBE and BTEX were higher during repairing than non-repairing. MTBE and toluene had the highest concentration among the analysis compounds and for all sampling sites. This result showed that the level of MTBE and BTEX were mainly from the emissions of both traffic and industrial sources. MTBE and BTEX ratio averaged 11.8:2.7:9.3:1.0:3.5, respectively. T/B ratio ranged from 0.5 to 12.3. This result was associated with the photochemical ages of air parcel and the characteristics of emission sources. The correlation between MTBE and BTEX in all sampling sites were also explained by principal component analysis (PCA). For industrial areas, three factors were extracted. For traffic intersection, night market and parking area, only one factor was extracted. Two factors were extracted for motor vehicle repairing plant. In this study, except for motor vehicle repairing plant, the cancer risks exposured by MTBE and benzene were below the acceptable level of 1×10-5 and non-carcinogenic risk were below 1.0. This result reveals that the risk of exposurement for all sampling sites was acceptable in this study. However, the potential health risk at one motor vehicle repairing in plant this study during repairing time was high and, therefore, it might be worth to confirm the possible sources in the future.

Il est reconnu que le benzène, le toluène, l’éthylbenzène et les isomères du xylène, composés organiques volatils (COVs) communément désignés BTEX, produisent des effets nocifs sur la santé humaine et sur les végétaux dépendamment de la durée et des niveaux d’exposition. Le benzène en particulier est classé cancérogène et une exposition à des concentrations supérieures à 64 g/m3 de benzène peut être fatale en 5–10 minutes. Par conséquent, la mesure en temps réel des BTEX dans l’air ambiant est essentielle pour détecter rapidement un danger associé à leur émission dans l’air et pour estimer les risques potentiels pour les êtres vivants et pour l’environnement. Dans cette thèse, une méthode d’analyse en temps réel des BTEX dans l’air ambiant a été développée et validée. La méthode est basée sur la technique d’échantillonnage direct de l’air couplée avec la spectrométrie de masse en tandem utilisant une source d’ionisation chimique à pression atmosphérique (APCI-MS/MS directe). La validation analytique a démontré la sensibilité (limite de détection LDM 1–2 μg/m3), la précision (coefficient de variation CV < 10%), l’exactitude (exactitude > 95%) et la sélectivité de la méthode. Des échantillons d’air ambiant provenant d’un site d’enfouissement de déchets industriels et de divers garages d’entretien automobile ont été analysés par la méthode développée. La comparaison des résultats avec ceux obtenus par la technique de chromatographie gazeuse on-line couplée avec un détecteur à ionisation de flamme (GC-FID) a donné des résultats similaires. La capacité de la méthode pour l’évaluation rapide des risques potentiels associés à une exposition aux BTEX a été prouvée à travers une étude de terrain avec analyse de risque pour la santé des travailleurs dans trois garages d’entretien automobile et par des expériences sous atmosphères simulées. Les concentrations mesurées dans l’air ambiant des garages étaient de 8,9–25 µg/m3 pour le benzène, 119–1156 µg/m3 pour le toluène, 9–70 µg/m3 pour l’éthylbenzène et 45–347 µg/m3 pour les xylènes. Une dose quotidienne environnementale totale entre 1,46 10-3 et 2,52 10-3 mg/kg/jour a été déterminée pour le benzène. Le risque de cancer lié à l’exposition environnementale totale au benzène estimé pour les travailleurs étudiés se situait entre 1,1 10-5 et 1,8 10-5. Une nouvelle méthode APCI-MS/MS a été également développée et validée pour l’analyse directe de l’octaméthylcyclotétrasiloxane (D4) et le décaméthylcyclopentasiloxane (D5) dans l’air et les biogaz. Le D4 et le D5 sont des siloxanes cycliques volatils largement utilisés comme solvants dans les processus industriels et les produits de consommation à la place des COVs précurseurs d’ozone troposphérique tels que les BTEX. Leur présence ubiquitaire dans les échantillons d’air ambiant, due à l’utilisation massive, suscite un besoin d’études de toxicité. De telles études requièrent des analyses qualitatives et quantitatives de traces de ces composés. Par ailleurs, la présence de traces de ces substances dans un biogaz entrave son utilisation comme source d’énergie renouvelable en causant des dommages coûteux à l’équipement. L’analyse des siloxanes dans un biogaz s’avère donc essentielle pour déterminer si le biogaz nécessite une purification avant son utilisation pour la production d’énergie. La méthode développée dans cette étude possède une bonne sensibilité (LDM 4–6 μg/m3), une bonne précision (CV < 10%), une bonne exactitude (> 93%) et une grande sélectivité. Il a été également démontré qu’en utilisant cette méthode avec l’hexaméthyl-d18-disiloxane comme étalon interne, la détection et la quantification du D4 et du D5 dans des échantillons réels de biogaz peuvent être accomplies avec une meilleure sensibilité (LDM ~ 2 μg/m3), une grande précision (CV < 5%) et une grande exactitude (> 97%). Une variété d’échantillons de biogaz prélevés au site d’enfouissement sanitaire du Complexe Environnemental de Saint-Michel à Montréal a été analysée avec succès par cette nouvelle méthode. Les concentrations mesurées étaient de 131–1275 µg/m3 pour le D4 et 250–6226 µg/m3 pour le D5. Ces résultats représentent les premières données rapportées dans la littérature sur la concentration des siloxanes D4 et D5 dans les biogaz d’enfouissement en fonction de l’âge des déchets.<br>It is known that benzene, toluene, ethylbenzene and xylene isomers, volatile organic compounds (VOCs) commonly called BTEX, have toxic health effects on humans and plants depending on duration and levels of exposure. Benzene in particular is classified carcinogenic, and exposure to benzene at concentrations above 64 g/m3 can be fatal within 5–10 minutes. Therefore, real-time monitoring of BTEX in ambient air is essential for the early warning detection associated with their release and in estimating the potential exposure risks to living beings and the environment. In this thesis, a real-time analysis method for BTEX in ambient air was developed and validated. The method is based on the direct-air sampling technique coupled with tandem mass spectrometry using atmospheric pressure chemical ionization (direct APCI-MS/MS). Validation of the method has shown that it is sensitive (limit of detection LOD 1–2 μg/m3), precise (relative standard deviation RSD < 10%), accurate (accuracy > 95%) and selective. Ambient air samples from an industrial waste landfill site and various automobile repair shops were analyzed by the developed method. Comparison of results with those obtained by online gas chromatography coupled with a flame ionization detector (GC-FID) technique exhibited similar results. The capacity of the method for the fast evaluation of potential risks associated with an exposure to BTEX has been demonstrated through a field study with health risk assessment for workers at three automobile repair shops and through experiments under simulated atmospheres. Concentrations measured in the ambient air of the garages were in the ranges of 8.9–25 µg/m3 for benzene, 119–1156 µg/m3 for toluene, 9–70 µg/m3 for ethylbenzene, and 45–347 µg/m3 for xylenes. A total environmental daily dose of 1.46 10-3–2.52 10-3 mg/kg/day was determined for benzene. The estimated cancer risk due to the total environmental exposure to benzene was between 1.1 10-5 and 1.8 10-5 for the workers studied. A novel APCI-MS/MS method was also developed and validated for the direct analysis of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in air and biogases. D4 and D5 are cyclic volatile siloxanes widely used in industrial processes and consumer products as replacement solvents for the tropospheric ozone forming VOCs, such as BTEX. Their ubiquitous presence in ambient air samples, due to the growing consumption, raises the need for toxicity studies which require qualitative and quantitative trace analysis of these compounds. Furthermore, the presence of trace amounts of these substances in a biogas hampers its use as a source of renewable energy by causing expensive damages to the equipment. Thus, siloxane analysis of the biogas is essential in determining if purification is needed before the use for energy production. The method developed in this study for these aims has good sensitivity (LOD 4–6 μg/m3), good precision (RSD < 10%), good accuracy (> 93%) and high selectivity. It was also shown that by using this method with hexamethyl-d18-disiloxane as an internal standard, detection and quantification of D4 and D5 in real biogas samples can be done with a better sensitivity (LOD ~ 2 μg/m3), high precision (RSD < 5%), and high accuracy (> 97%). Various biogas samples collected from the landfill site of the Complexe Environnemental de Saint-Michel in Montreal have been successfully analyzed by this new method. Concentrations measured were in the ranges of 131–1275 µg/m3 for D4 and 250–6226 µg/m3 for D5. These results represent the first primary-literature-reported data on siloxanes D4 and D5 contents of landfill-derived biogases as a function of the refuse age.