143 research outputs found

    Effect of aging on decorative and renovation products containing biocides: Assessment of its impact on indoor air quality

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    To evaluate the impact of the aging (the use of detergent and exposure to light, high relative humidity, and temperature) on the efficiency of biocides present in the renovation plaster after being added to polyester cellulose (combined material) and on VOC and SVOC emissions, an inoculation of innate and aged materials with fungal spores was carried out in this study using a dry aerosolization system. VOCs and SVOCs emitted from these different materials before and after inoculation were characterized using gas (TD-GCMS/ FID) and liquid (HPLC) chromatography.publishedVersio

    Validity and limitations of simple reaction kinetics to calculate concentrations of organic compounds from ion counts in PTR-MS

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    In September 2017, we conducted a proton-transfer-reaction mass-spectrometry (PTR-MS) intercomparison campaign at the CESAR observatory, a rural site in the central Netherlands near the village of Cabauw. Nine research groups deployed a total of 11 instruments covering a wide range of instrument types and performance. We applied a new calibration method based on fast injection of a gas standard through a sample loop. This approach allows calibrations on timescales of seconds, and within a few minutes an automated sequence can be run allowing one to retrieve diagnostic parameters that indicate the performance status. We developed a method to retrieve the mass-dependent transmission from the fast calibrations, which is an essential characteristic of PTR-MS instruments, limiting the potential to calculate concentrations based on counting statistics and simple reaction kinetics in the reactor/drift tube. Our measurements show that PTR-MS instruments follow the simple reaction kinetics if operated in the standard range for pressures and temperature of the reaction chamber (i.e. 1-4 mbar, 30-120 degrees, respectively), as well as a reduced field strength E/N in the range of 100-160 Td. If artefacts can be ruled out, it becomes possible to quantify the signals of uncalibrated organics with accuracies better than +/- 30 %. The simple reaction kinetics approach produces less accurate results at E/N levels below 100 Td, because significant fractions of primary ions form water hydronium clusters. Deprotonation through reactive collisions of protonated organics with water molecules needs to be considered when the collision energy is a substantial fraction of the exoergicity of the proton transfer reaction and/or if protonated organics undergo many collisions with water molecules.Peer reviewe

    Etude de quelques intermediaires reactionnels d'un compose alpha-dicarbonyle, le benzile, par spectrometrie Raman de resonance resolue dans le temps

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    SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : TD 81027 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

    Évolution spatio-temporelle des teneurs en composés organiques volatils en atmosphère urbaine et périurbaine et contribution de leurs sources

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    En France, la mesure des 31 COV de la directive 2002/3/CE est effectuée par les Associations Agréées de Surveillance de la Qualité de l'Air (AASQA). Pour les sites de Marseille, Paris, Grenoble et Strasbourg, la mesure horaire en continu de ces composés est accomplie depuis 2001. Ces travaux présentent l'adaptation de la chaîne et des conditions analytiques à la mesure de 17 COV chlorés toxiques supplémentaIres. Les différences et les similitudes des quatre sites de mesure ont été ensuite analysées au travers de l'étude des évolutions temporelles et spatiales des concentrations ambiantes. Les résultats montrent que le site de Marseille présente des teneurs moyennes en COV deux à trois fois plus élevées que celle des trois autres sites. En outre, quel que soit le site, une grande majorité des composés semble résulter des sources liées au trafic urbain. Cependant, quelques composés ont un comportement singulier. Ainsi, pour le site de Marseille, les concentrations en benzène sont très influencées par les émissions d'une usine relativement éloignée. Cette étude est également la première en France à expliciter les résultats de deux modèles sources-récepteurs permettant d'évaluer les contributions des différentes sources à l'origine des teneurs ambiantes. Pour chacun d'eux et pour chaque site, quelques sources communes ont été trouvées échappement automobile, évaporation d'essence, fuites de gaz, source biotique et chauffage domestique. Ainsi, quel que soit le site de mesure, la source échappement d'automobile est la plus importante (entre 20 et 60% des contributions totales). Enfin, pour Strasbourg, les résultats ont été confrontés à ceux issus de l'inventaire d'émission.LILLE1-BU (590092102) / SudocSudocFranceF

    Improvement in 8h-sampling rate assessment considering meteorological parameters variability for biogas VOC passive measurements in the surroundings of a French landfill

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    WOS:000363346200042International audiencePassive sampling technology has been extensively used for long-term VOC atmospheric concentrations' monitoring. Its performances regarding the short-term measurements and related to VOC from biogas were evaluated in this work: laboratory scale experiments have been conducted in order to check the suitability of Radiello (R) diffusive samplers for the assessment of 8 h-VOC levels in highly changeable meteorological conditions; in a second step a short pilot field campaign was implemented in the vicinity of a West-French landfill. First of all, it was assessed that amongst a diversified list of 16 characteristic compounds from biogas, mercaptans, some halogenated, oxygenated compounds and terpenes could not be measured accurately by this passive technique either because they are not captured by the sorbent or they are not quantitatively desorbed in the chosen mediated analytical conditions. Moreover, it has been confirmed that sampling rates (SR) related to isopentane, THF, cyclohexane, toluene, p-xylene and n-decane are influenced by environmental factors: the main influence concerns the wind speed. From 2 m s(-1), when the velocity increases by 1 m s(-1), the SR increases from 12 to 32% depending on the COV (considering a linear dependence between 2 and 7 m s(-1)). Humidity has no effect on SR, and temperature influence is rather limited to less than 3% per degree. A comprehensive uncertainty estimation, including uncertainties linked to meteorological changes, has led to global relative uncertainties comprising between 18% and 54% from one VOC to another: a quite high value comparatively to those obtained without considering meteorological condition influences. To illustrate our results, targeted VOC were quantified in the field, on a single day: concentrations range between LD to 3 mu g m(-3): relatively very low concentrations compared to those usually reported by literature

    Etude de COV oxygénés et biogéniques en milieu rural (du développement métrologique à l'évaluation de l'impact sur la chimie atmosphérique)

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    Les Composés Organiques Volatils (COV) forment une classe de composés variés, jouant un rôle clef dans la chimie atmosphérique et ayant des impacts sur le climat, l environnement et la santé. De récentes études suggèrent l implication de COV oxygénés ou biogéniques dans la formation de polluants secondaires tels les aérosols organiques secondaires et l ozone. Ces COV, présents en zone rurale, sont peu renseignés quant à la variabilité de leurs sources et l évolution de leurs teneurs ambiantes. Cette thèse a pour but d améliorer les connaissances sur leur comportement en zone rurale pour une meilleure compréhension de leur rôle dans la chimie atmosphérique. La démarche suivie a reposé sur le développement métrologique et des campagnes de mesure pour constituer une base de données représentative. Des méthodes de mesure ont été adaptées et/ou développées pour la mesure de plus de 80 COV en zone rurale, incluant : 54 COV de C1 à C10 par préconcentration/thermodésorption et analyse par GC-FID on-line ; 21 composés carbonylés de C1 à C6 par dérivation chimique, désorption chimique et analyse par HPLC/UV ; 5 composés aromatiques, 6 aldéhydes de C6 à C11, 6 monoterpènes et 13 alcanes de C9 à C16 par préconcentration/thermodésorption et analyse par GC/FID-MS. Ces méthodes, utilisées dans 2 campagnes de mesure en Mars et Juin 2009 au site de Peyrusse-Vieille (Gers, France), a permis la collecte d un vaste jeu de données. Son analyse a permis de déterminer les niveaux des COV ciblés en zone rurale, leurs évolutions temporelles et les paramètres les influençant. Furent également soulignés les mécanismes de transport et l impact des espèces biogéniques sur la chimie atmosphérique.Volatile Organic Compounds (VOC) constitutes a heterogeneous compounds class, which play a significant part in atmospheric chemistry, impacting climate, environment and health. Recent studies have suggested the implication of biogenic and oxygenated VOCs in the formation processes of secondary species, such as ozone or Secondary Organic Aerosols. Little is known about those compounds, well represented in remote areas; mostly toward their ambient levels and diurnal and seasonal evolutions. This thesis objectives are to improve the current knowledge about their behavior in remote areas, for a better understanding of their part in atmospheric chemistry. The method adopted consisted in metrological development and field campaigns, to constitute a representative data base. Measurement methods were optimized and/or developed for the measure of: 54 NMHCs from C2 to C10, using préconcentration/thermodesorption coupled with GC/FID on-line analysis; 21 carbonyl compounds from C1 to C6, by chemical derivatization and chemical desorption coupled with HPLC/UV analysis; and 5 aromatic compounds, 6 aldehydes from C6 to C11, 6 monoterpenes and 6 alkanes from C9 to C16; by preconcentration coupled with thermodesorption and GC/FID-MS analysis. Those methods were used during two measurement campaigns, in March and June 2009, at the remote site of Peyrusse-Vieille (Gers, France). They permitted to collect an important database, whose analysis allowed determining the target compounds ambient levels, temporal variations, and the parameters inducing these observations. A thorough analysis then underlined the part transport mechanisms and importance of biogenic species in remote areas.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF
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