Volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) constitute important classes of indoor contaminants. Emissions of VOCs and SVOCs from myriad building materials and consumer products cause high indoor concentrations with health risks that may be orders-of-magnitude greater than outdoors. The need to control VOC and SVOC emissions from interior materials and thereby reduce indoor concentrations is made more urgent by the prevailing drive for air-tight, energy efficient buildings. To develop low-emission products, emission rates are usually measured in emission chambers. However, there are three significant problems associated with chamber tests: (1) VOC emissions testing procedures of individual laboratories are frequently subject to error and uncertainty; (2) SVOC emissions testing in chambers is extremely difficult and time-consuming, and also subject to error and uncertainty; and (3) chamber tests provide little insight into the mechanisms controlling emissions. This research aimed to solve these problems by developing reference materials for VOC and SVOC emissions testing. Formaldehyde was studied separately from other VOCs because of its unusual properties. Emission mechanisms, and the related modeling approaches for predicting emissions, were investigated by reviewing the literature and performing chamber studies. Based on the internally controlled VOC and formaldehyde emission mechanisms, diffusion-controlled reference materials, which mimic real sources, were created for VOCs and formaldehyde. Approaches for developing externally controlled reference materials for SVOC emissions testing were also explored. Appropriate mechanistic models can predict the true emission rates of the reference materials and therefore provide reference values to validate emissions testing results and certify procedures of individual laboratories. The potential of a solid phase microextraction (SPME) method was also evaluated and found to be a promising technique that can be used in chamber tests to simplify and improve sampling and analytical procedures. This research elucidates the mass-transfer mechanisms of VOC and SVOC emissions and provides practical approaches for developing reference materials for emissions testing. The fundamental understanding and methodological advances will enhance indoor air quality science, improve the emissions testing industry, and provide a sound basis on which to develop standards and regulations. / Ph. D.

The investigation of the atmospheric fate and transport of semi-volatile organic compounds (SOCs) often requires the sampling of large volumes of air (>100 m3) in a relatively short period of time. Conventionally high-volume pumps are not suitable for remote areas without access to reliable network power. We have developed a flow through sampler for such situations. It consists of a horizontally-oriented flow-tube, that can collect gaseous and particle-bound SOCs from large volumes of air by turning into the wind and having the wind blow through a porous sampling medium such as polyurethane foam. Through both indoor and outdoor experiments, we quantified its air sampling rate (through battery operated anemometers inside and outside of the flow tube), its sampling efficiency (by theoretical plate number analysis of the break-though curves for PCBs, PAHs, OCPs and PBDEs), and its accuracy (by comparison of concentrations, time trends, temperature dependences and isomer ratios with those obtained by conventional high-volume sampling) under conditions of constant and variable meteorological conditions (wind speed, temperature). The flow-through sampler was deployed to monitor SOC concentrations at a remote Chinese research station located close to Nam Co Lake, Tibet. During the campaign, fifteen 1 month-long samples were taken, corresponding to sample volumes between 5,000 and 20,000 m3. Despite those large sample volumes, only HCB and HCHs experienced break-through, but application of frontal chromatograph theory allows the estimation of breakthrough-corrected air concentrations even for those relatively volatile SOCs. The pesticide levels at Nam Co are generally very low. Most pesticides had higher levels during summer, resulting in a strong temperature dependence. This is correlated with air mass origin across the Himalayas in the Gangetic plains of India and Bangladesh. The flow through sampler constitutes a feasible method for reliably and quantitatively collecting SOCs from large air volumes.

Submitted by Márcio Justi Laranja (marciojusti21@gmail.com) on 2018-05-28T15:19:36Z No. of bitstreams: 1 dissertação(versão final).pdf: 4313795 bytes, checksum: fef2f9c53ba336958ef95fc671df0d72 (MD5) / Approved for entry into archive by Paula Torres Monteiro da Torres (paulatms@sjrp.unesp.br) on 2018-05-28T16:41:46Z (GMT) No. of bitstreams: 1 laranja_mj_me_sjrp_int.pdf: 4313795 bytes, checksum: fef2f9c53ba336958ef95fc671df0d72 (MD5) / Made available in DSpace on 2018-05-28T16:41:46Z (GMT). No. of bitstreams: 1 laranja_mj_me_sjrp_int.pdf: 4313795 bytes, checksum: fef2f9c53ba336958ef95fc671df0d72 (MD5) Previous issue date: 2018-05-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A carbonização hidrotérmica (CHT) é um processo de conversão termoquímica, capaz de usar uma biomassa úmida como matéria-prima e convertê-la em um produto sólido rico em carbono orgânico, denominado carvão hidrotérmico, passível de aplicação ao solo. No processo também é obtida como produto uma fração líquida contendo uma variedade de compostos orgânicos de interesse comercial e/ou tóxicos ao ambiente, denominada água de processo. Nesse trabalho, bagaço de cana e/ou vinhaça foram submetidos ao processo de CHT, sob diferentes condições reacionais. Assim, foram avaliados os efeitos do tipo de biomassa e das variáveis do processo (tempo, temperatura e porcentagem de adição de ácido fosfórico) sobre a composição do carvão hidrotérmico e da água de processo, em relação aos compostos orgânicos semivoláteis (SVOC) e voláteis (VOC). Para isso, foi realizada a extração de SVOC no carvão hidrotérmico e na água de processo utilizando extração ultrassônica e extração líquido-líquido, respectivamente. Já os VOC foram extraídos com o método do headspace associado à microextração em fase sólida (HS-SPME). Os compostos orgânicos foram identificados por cromatografia em fase gasosa acoplada à espectrometria de massas (GC-MS). Os principais SVOC identificados no carvão hidrotérmico foram fenóis, ácidos carboxílicos, cetonas e compostos nitrogenados, indicando que este material contém funções orgânicas importantes e incorporação de nitrogênio, sendo estas características desejáveis para uma possível aplicação em solo. O tipo de biomassa carbonizada, a temperatura e adição de ácido fosfórico (H3PO4) durante o processo CHT mostraram ter grande influência nos SVOC identificados tanto no carvão hidrotérmico quanto na água de processo, enquanto o efeito do tempo não foi significativo. Condições de temperatura elevada e maior porcentagem de H3PO4 promoveram, respectivamente, maior aromatização e funcionalização do carvão hidrotérmico. Além disso, a adição de ácido na CHT provocou a diminuição de compostos fenólicos e furânicos e aumento de ácidos carboxílicos e cetonas na água de processo. Os principais VOC identificados foram aldeídos, cetonas, fenóis, furanos e compostos nitrogenados. O aumento da temperatura promoveu a degradação dos aldeídos e aumento de cetonas e fenóis no carvão hidrotérmico. Já a adição de H3PO4 afetou a degradação dos compostos nitrogenados no carvão hidrotérmico e na água de processo. / Hydrothermal carbonization (HTC) is a thermochemical conversion process, able to use a moisture biomass as raw material and convert it into a solid product rich in organic carbon, called hydrochar, amenable to application to the soil. In the process, a liquid fraction is also obtained as product containing a variety of organic compounds, of commercial interest and/or toxic to the environment, called process water. In this work, sugarcane bagasse and vinasse were submitted to the HTC process, in different reaction conditions. Thus, the effects of the biomass type and the process variables were evaluated (time, temperature and percentage of phosphoric acid addition) on the composition of hydrochar and process water in the case of semi-volatile organic compounds (SVOC) and volatile organic compounds (VOC). For this, the SVOC extraction from the hydrochar and the process water were performed using ultrasonic extraction and liquid-liquid extraction, respectively. The VOC extraction was performed by headspace-solid phase microextraction (HS-SPME) method. The identification of organic compounds was performed by gas chromatography-mass spectrometry (GC-MS). The SVOC were identified, with mainly phenols, carboxylic acids, ketones and nitrogen compounds obtained, indicating that the hydrochar produced contains important organic functions and nitrogen incorporation into the material, desirable characteristics for a soil application. The pattern of SVOC obtained both in hydrochar and in process water showed great dependence on the type of carbonized biomass and with the carbonization temperature and phosphoric acid addition, while the effect of time was not significant. High temperature and higher H3PO4 percentage conditions promoted, respectively, greater aromatization and functionalization of the hydrochar. Furthermore, the addition of acid in HTC caused the decrease of phenolic compounds and furans and increased carboxylic acids and ketones in process water. The VOC were identified, with mainly aldehydes, ketones, phenols, furans and nitrogen compounds. The increase in temperature promoted degradation of aldehydes and increase of ketones and phenols in the hydrochar. On the other hand, the H3PO4 addiction affected the degradation of the nitrogen compounds in the hydrochar and process water.

The investigation of the atmospheric fate and transport of semi-volatile organic compounds (SOCs) often requires the sampling of large volumes of air (>100 m3) in a relatively short period of time. Conventionally high-volume pumps are not suitable for remote areas without access to reliable network power. We have developed a flow through sampler for such situations. It consists of a horizontally-oriented flow-tube, that can collect gaseous and particle-bound SOCs from large volumes of air by turning into the wind and having the wind blow through a porous sampling medium such as polyurethane foam. Through both indoor and outdoor experiments, we quantified its air sampling rate (through battery operated anemometers inside and outside of the flow tube), its sampling efficiency (by theoretical plate number analysis of the break-though curves for PCBs, PAHs, OCPs and PBDEs), and its accuracy (by comparison of concentrations, time trends, temperature dependences and isomer ratios with those obtained by conventional high-volume sampling) under conditions of constant and variable meteorological conditions (wind speed, temperature). The flow-through sampler was deployed to monitor SOC concentrations at a remote Chinese research station located close to Nam Co Lake, Tibet. During the campaign, fifteen 1 month-long samples were taken, corresponding to sample volumes between 5,000 and 20,000 m3. Despite those large sample volumes, only HCB and HCHs experienced break-through, but application of frontal chromatograph theory allows the estimation of breakthrough-corrected air concentrations even for those relatively volatile SOCs. The pesticide levels at Nam Co are generally very low. Most pesticides had higher levels during summer, resulting in a strong temperature dependence. This is correlated with air mass origin across the Himalayas in the Gangetic plains of India and Bangladesh. The flow through sampler constitutes a feasible method for reliably and quantitatively collecting SOCs from large air volumes.

No description available.

Modern indoor environments contain a vast array of contaminating sources. Emissions from these sources produce contaminant concentrations that are substantially higher indoors than outside. Because we spend most of our time indoors, exposure to indoor pollutants may be orders-of-magnitude greater than that experienced outdoors. Phthalate esters have been recognized as major indoor pollutants. They are mainly used as plasticizers to enhance the flexibility of polyvinylchloride (PVC) products, as well as in humectants, emollients, and antifoaming agents. Phthalates are found in a wide range of consumer products including floor and wall coverings, car interior trim, floor tiles, gloves, footwear, insulation on wiring, and artificial leather. Because these phthalate additives are not chemically bound to the polymer matrix, slow emission from the products to the surrounding air or other media usually occurs. Biomonitoring data suggest that over 75% of the U.S. population is exposed to phthalates. The ubiquitous exposure to phthalates is of concern because toxicological investigations have demonstrated considerable adverse health effects of phthalates and their metabolites. Studies have shown that exposure to phthalates results in profound and irreversible changes in the development of the reproductive tract, especially in males, raising the possibility that phthalate exposures could be the leading cause of reproductive disorders in humans. In addition, effects such as increases in prenatal mortality, reduced growth and birth weight, skeletal, visceral, and external malformations are possibly associated with phthalate exposure. Epidemiologic studies in children also show associations between phthalate exposure in the home and the risk of asthma and allergies. Given the ubiquitous nature of phthalates in the environment and the potential for adverse human health impacts, there is a critical need to understand indoor emissions of phthalates and to identify the most important sources and pathways of exposure. In this study, a model that integrates the fundamental mechanisms governing emissions of semi-volatile organic compounds (SVOCs) from polymeric materials and their subsequent interaction with indoor surfaces and airborne particles was developed. The emissions model is consistent with analogous mechanistic models that predict emission of volatile organic compounds (VOCs) from building materials. Reasonable agreement between model predictions and gas-phase di-2-ethylhexyl phthalate (DEHP) concentrations was achieved for data collected in a previously published experimental study that measured emissions of DEHP from vinyl flooring in two very different chambers. The analysis showed that while emissions of highly volatile VOCs are subject to “internal“ control (through the material-phase diffusion coefficient), emissions of the very low volatility SVOCs are subject to “external“– control (through partitioning into the gas phase, the convective mass transfer coefficient, and adsorption onto interior surfaces). Because of the difficulties associated with sampling and analysis of SVOCs, only a few chamber studies quantifying their emissions from building materials and consumer products are available. To more rigorously validate the SVOCs emission model and more completely understand the mechanisms governing the release of phthalate from polymeric building materials, the emission of DEHP from vinyl flooring was studied for up to 140 days in a specially-designed stainless steel chamber. In the duplicate chamber study, the gas-phase concentration in the chamber increased slowly and reached a steady state level of 0.9 µg/m3 after 30 days. By increasing the area of vinyl flooring and decreasing that of the stainless steel surface in the chamber, the time to reach steady state was significantly reduced, compared to the previous study (1 month vs. 5 months). The adsorption isotherm of DEHP on the interior stainless steel chamber surface was explicitly measured using two different methods (solvent extraction and thermal desorption). Strong adsorption of DEHP onto the stainless steel surface was observed and found to follow a simple linear relationship. In addition, parameters measured in the experiments were then applied in the fundamental SVOCs emission model. Good agreement was obtained between the predictions of the model and the gas-phase DEHP chamber concentrations, without resorting to fitting of model parameters. These chamber studies have shown that the tendency of SVOCs to adsorb strongly to interior surfaces has a very strong influence on the emission rate. Compared to the experimental chamber systems, however, the real indoor environment has many other types of surface that will adsorb phthalates to different extents. The emission rate measured in a test chamber may therefore be quite different to the emission rate from the same material in the indoor environment. For this reason, both a two-room model and a more representative three-compartment model were developed successively to estimate the emission rate of DEHP from vinyl flooring, the evolving gas-phase and adsorbed surface concentrations, and human exposures (via inhalation, dermal absorption and oral ingestion of dust) in a realistic indoor environment. Adsorption isotherms for phthalates and plasticizers on interior surfaces, such as carpet, wood, dust and human skin, were derived from previous field and laboratory studies. A subsequent sensitivity analysis revealed that the vinyl flooring source characteristics, as well as mass-transfer coefficients and ventilation rates, are important variables influencing the steady-state DEHP concentration and resulting exposures. A simple uncertainty analysis suggested that residential exposure to DEHP originating from vinyl flooring may fall somewhere between about 5 µg/kg/d and 180 µg/kg/d. The roughly 40-fold range in exposure reveals the inherent difficulty in using biomonitoring results to identify specific sources of exposure in the general population. This research represents the first attempt to explicitly elucidate the fundamental mechanisms governing the release of phthalates from polymeric building materials as well as their subsequent interaction with interior surfaces. The mechanistic models developed can most likely be extended to predict concentration and exposure arising from other sources of phthalates, other sources of other semi-volatile organic compounds (such as biocides and flame retardants), as well as emissions into other environmental media (food, water, saliva, and even blood). The results will be of value to architects, governments, manufacturers, and engineers who wish to specify low-emitting green materials for healthy buildings. It will permit health professionals to identify and control health risks associated with many of the SVOCs used in indoor materials and consumer products in a relatively inexpensive way. / Ph. D.

Depuis quatre décennies, la prévalence des affections respiratoires chroniques de l'enfant a considérablement augmenté dans les pays développés. Les conditions de survenue de ces affections sont complexes, mais de nombreux travaux suggèrent la contribution importante de l'exposition par inhalation aux polluants de l'air intérieur. Dans ce contexte, cette thèse vise à évaluer l’exposition cumulée à une gamme de polluants chimiques et biologiques de l’air intérieur dans un échantillon donné de logements. Il a également pour objectif de créer une typologie des logements en fonction de leur multi-contamination, et vise à construire des modèles explicatifs des concentrations des polluants en fonction des caractéristiques de l’habitat et des habitudes de vie des occupants.Une enquête environnementale a été menée dans 150 logements issus de la cohorte Pélagie, suivie en Bretagne depuis 2002. Des prélèvements ont permis de mesurer la concentration de 8 aldéhydes, 4 THM, 22 autres COV, 9 COSV et 4 genres de moisissures dans l’air de ces logements. Celles-ci, ainsi que 4 allergènes ont également été dosés dans des échantillons de poussières. Les paramètres d’ambiance (température, humidité relative et dioxyde de carbone) ont été mesurés. Un questionnaire renseigné par les familles a permis de collecter des informations sur les logements et leurs occupants : structure et historique du bâtiment, revêtements, ménage, chauffage, aération, utilisation de certains produits ou réalisation d’activités particulières. Ces données ont été analysées par des approches statistiques multivariées, et des modèles de régression linéaire et logistique ont été mis en oeuvre pour relier les concentrations des contaminants aux caractéristiques des logements. Ces mesures ont mis en évidence une contamination importante et systématique des logements par une grande part des contaminants chimiques et biologiques, à des niveaux parfois élevés au regard d’études comparables et des valeurs guides lorsqu’elles existent. Des analyses en composantes principales ont permis de mettre en évidence des sous-groupes de composés qui ont pu être interprétés en termes de sources, et de sélectionner un certain nombre de composés traceurs représentatifs de chaque sous-groupe. Une analyse factorielle multiple a permis de répartir les logements en 7 classes, chacune présentant un profil de multi-contamination particulier. Enfin, les modèles de régression linéaire et logistique construits pour les composés traceurs permettent d’expliquer entre 5 et 60% de la variabilité des concentrations, et mettent en évidence la multiplicité des sources, l’importance de la description précise des environnements intérieurs, et l’impact des paramètres d’ambiance sur ces concentrations. Ce travail décrit donc une contribution importante à l’évaluation des expositions aux contaminants de l’air intérieur et fournit un certain nombre d’éléments quant à la prédiction des expositions dans les environnements intérieurs. / For the last four decades, the prevalence of chronic respiratory affections in children has increased dramatically in developed countries. Occurring conditions of these affections are complex, but many studies suggest the important contribution of inhalation exposure to indoor air pollutants. In this context, this thesis aims to assess the cumulative exposure to a range of chemical and biological pollutants in indoor air in a given sample of dwellings. It also aims to create a typology of these dwellings based on their multi-contamination, and to build explanatory models for concentrations of pollutants based on characteristics of the dwellings and lifestyle of the occupants. An environmental survey was conducted in 150 dwellings from the Pelagie cohort, followed in Brittany since 2002. We measured the concentration of 8 aldehydes, 4 THMs, 22 other VOCs, 9 SVOCs and 4 mold genera in the air of these dwellings. Molds as well as four allergens were also measured in dust samples. Ambient parameters (temperature, relative humidity and carbon dioxide) were also measured. A questionnaire completed by families allowed collecting information on dwellings and their occupants: structure and history of the building, wall and floor coatings, cleaning, heating and ventilation habits, use of certain products or performing specific activities. These data were analyzed by multivariate statistical approaches, and linear and logistic regression models were used to link the concentrations of the contaminants with the housing characteristics. These measures showed an important and systematic contamination of the dwellings by a large amount of both chemical and biological contaminants, sometimes at relatively high levels regarding comparable studies and guideline values when they exist. Principal components analysis allowed to identify subgroups of compounds that could be interpreted in terms of sources, and to select representative compounds of each subgroup. A multiple factor analysis was used to classify the dwellings into 7 categories, each with a special multi-contamination profile. Finally, linear and logistic regression models built for the representative compounds explained between 5 and 60% of the variability of the concentrations, and highlighted the multiplicity of sources, the importance of a precise description of indoor environments, and the impact of the ambient parameters on these concentrations. This work thus describes an important contribution to the exposure assessment to indoor air contaminants and provides elements for prediction of exposures in indoor environments.