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Design of an environmental chamber for the study of atmospheric chemistry: New developments in the analytical device
Abstract
An indoor evacuable environmental chamber has been built at Lisa. The photoreactor is made of Pyrex tube and is equipped with an irradiation device to study photochemical reactions in the UV and visible ranges. A UV-visible DOAS and a long-path FT-IR spectrometry device have been designed to perform analyses of trace components of reactional mixtures during atmospheric simulation experiments. These facilities are unique in France and new developments have been designed and performed in the analytical device to allow a very long path and high stability of the optical path. The entire apparatus is described and the results of calibration experiments are given.
... In the case of kinetics studies, Teflon bags of several litres to a few cubic-meters working under atmospheric pressure and ambient temperature under artificial irradiation (generally UV fluorescent tube) were often used to apply relative rate methods (Brauers and Finlayson-Pitts 1997). Nevertheless, the atmospheric fate of hundreds of various volatile organic compounds (VOC) was also studied-and is still-in rigid chambers such as the one displayed in Fig. 1.4 (Barnes et al. 1987;Doussin et al. 1997;Etzkorn et al. 1999;Picquet-Varrault et al. 2001;Atkinson 2000). This systematic kinetic and mechanistic work has produced over time a comprehensive database that has established the foundations of most chemical schemes used in numerical models. ...
... Mirrors need to be mounted where they are unaffected by vibrations from fans or pumps and the mounting needs to be rigid with respect to changes in pressure or they need to be easily adjustable. Purge gas flows may be needed for Barnes et al. (1985), Doussin et al. (1997) (continued) ...
Atmospheric simulation chambers have been deployed with various research goals for more than 80 years. In this chapter, an overview of the various applications, including emerging new applications, is given. The chapter starts with a brief historical overview of atmospheric simulation chambers. It also provides an overview of how simulation chambers complement field observations and more classical laboratory experiments. The chapter is concluded with an introduction to the different aspects requiring consideration when designing an atmospheric simulation chamber.
... Briefly, the CSA chamber (LISA, Université Paris-Est Créteil) is an atmospheric simulation chamber, which is a cylindrical Pyrex reactor (volume: 977 L; length: 6 m; diameter: 45 cm) designed for investigating atmospheric gas processes under controlled conditions. In addition, it is equipped with instrumentation for analysis using ultraviolet-visible and infrared spectroscopy (Doussin et al., 1997;Picquet-Varrault et al., 2005). The chamber is equipped with an efficient homogenization system, ensuring a mixing time of less than 1 min. ...
Volatile organic compounds (VOCs) play a key role in tropospheric chemistry, giving rise to secondary products such as highly oxygenated organic molecules (HOMs) and secondary organic aerosols (SOAs). HOMs, a group of low-volatility gas-phase products, are formed through the autoxidation process of peroxy radicals (RO2) originating from the oxidation of VOCs. The measurement of HOMs is made by a NO3- ToFCIMS instrument, which also detects other species like small highly oxygenated VOCs (e.g., dicarboxylic acids) and sulfuric acid (H2SO4). The instrument response to HOMs is typically estimated using H2SO4, as HOMs are neither commercially available nor easily synthesized in the laboratory. The resulting calibration factor is then applied to quantify all species detected using this technique. In this study, we explore the sensitivity of the instrument to commercially available small organic compounds, primarily dicarboxylic acids, given the limitations associated with producing known amounts of HOMs for calibration. We compare these single-compound calibration factors to the one obtained for H2SO4 under identical operational conditions. The study found that the sensitivity of the NO3- ToFCIMS varies depending on the specific type of organic compound, illustrating how a single calibration factor derived from sulfuric acid is clearly inadequate for quantifying all detected species using this technique. The results highlighted substantial variability in the calibration factors for the tested organic compounds, with 4-nitrocatechol exhibiting the highest sensitivity and pyruvic acid the lowest. The obtained sulfuric acid calibration factor agreed well with the previous values from the literature. In summary, this research emphasized the need to develop reliable and precise calibration methods for progressively oxygenated reaction products measured with a NO3- chemical-ionization mass spectrometer (CIMS), for example, HOMs.
... Briefly, the CSA chamber (LISA, UPEC) is an atmospheric simulation chamber, which is a cylindrical Pyrex reactor (volume: 195 977 L, length: 6 m, diameter: 45 cm) designed for investigating atmospheric gas processes under controlled conditions. In addition, it is equipped with instrumentation for analysis using ultraviolet/visible and infrared spectroscopy (Doussin et al., 1997;Picquet-Varrault et al., 2005). The chamber is equipped with an efficient homogenization system, ensuring a mixing time of less than a 1 min. ...
Volatile organic compounds (VOCs) play a key role in tropospheric chemistry, giving rise to secondary products such as highly oxygenated organic molecules (HOMs) and secondary organic aerosols (SOA). HOMs, a group of low-volatility gas-phase products, are formed through the autoxidation process of peroxy radicals (RO2) originating from the oxidation of VOCs. The measurement of HOMs is made by a NO3¯ ToFCIMS instrument, which also detects other species like small highly oxygenated VOCs (e.g. dicarboxylic acids) and sulfuric acid (H2SO4). The instrument response to HOMs is typically estimated using H2SO4, as HOMs are neither commercially available nor easily synthesized in the laboratory. The resulting calibration factor is then applied to quantify all species detected using this technique. In this study, we explore the sensitivity of the instrument to commercially available small organic compounds, primarily dicarboxylic acids, given the limitations associated with producing known amounts of HOMs for calibration. We compare these single compound calibration factors to the one obtained for H2SO4 under identical operational conditions. The study found that the sensitivity of the NO3¯ ToFCIMS varies depending on the specific type of organic compound, illustrating how a single calibration factor derived from sulfuric acid is clearly inadequate for quantifying all detected species using this technique. The results highlighted substantial variability in the calibration factors for the tested organic compounds, with 4-nitrocatechol exhibiting the highest sensitivity, and pyruvic acid the lowest. The obtained sulfuric acid calibration factor agreed well with the previous values from the literature. In summary, this research emphasized the need to develop reliable and precise calibration methods for progressively oxygenated reaction products measure with NO3¯ CIMS, for example, HOMs.
... For evacuable chambers, dilution cleaning is often achieved by pumping the chamber down to high vacuum by mean of oil-free pumping systems involving combination of special rotary pumps, roots pump and/or turbomolecular pumps (Barnes et al. 1994;Doussin et al. 1997;Wang et al. 2011). Sometime the systems are completed with series of sorption pumps (De Haan et al. 1999). ...
When setting up a simulation chamber experiment it is essential, in order to ensure meaningful results, to start with a well-controlled chemical system. Coming after the chapter dealing with the requested careful characterization of the simulation chamber, the present chapter describes the preparation of the chamber before running an experiment. It includes various chamber cleaning protocols, the preparation of a clean chamber atmosphere (the reacting mixture) and a series of protocols for blank experiments. Indeed, having a clean atmosphere in a simulation chamber, as free as possible from both particulate and gaseous impurities, is essential to ensure high quality experimental results. As it may not be possible to have a perfectly clean chamber, blank experiments are crucial to both assess chamber cleanliness, account for impurities and establish uncertainties of the observed phenomena. In the present chapter, various cleaning protocols which involve the oxidation of the impurities, dilution, temperature degradation/evaporation, but the evacuation or manual cleaning are described as well. The various techniques to generate clean gas mixture—mostly clean O 2 , N 2 or water vapor, are discussed. Finally, complementarily to the reference experiments proposed in Chap. 2 , blank experiments to characterize walls chemical inertia, chamber-dependent radical sources or the presence of water-soluble species are also described.
... Kinetic experiments were performed in the CSA chamber. It is a 6 m long -977 L -Pyrex ® reactor (Doussin et al., 1997) equipped with a homogenization system allowing a mixing time below 1 min (Fouqueau et al., 2020b). This chamber has been designed for the investigation of gas-phase chemistry and is thus equipped with instruments dedicated to gas-phase monitoring. ...
Biogenic volatile organic compounds (BVOCs) are intensely emitted by forests and crops into the atmosphere. They can rapidly react with the nitrate radical (NO3) during the nighttime to form a number of functionalized products. Among them, organic nitrates (ONs) have been shown to behave as reservoirs of reactive nitrogen and consequently influence the ozone budget and secondary organic aerosols (SOAs), which are known to have a direct and indirect effect on the radiative balance and thus on climate.
Nevertheless, BVOC + NO3 reactions remain poorly understood. Thus, the primary purpose of this study is to furnish new kinetic and mechanistic data for one monoterpene (C10H16), terpinolene, and one sesquiterpene (C15H24), β-caryophyllene, using simulation chamber experiments. These two compounds have been chosen in order to complete the few experimental data existing in the literature. Rate constants have been measured using both relative and absolute methods. They have been measured to be (6.0 ± 3.8) ×10-11 and (1.8 ± 1.4) ×10-11 cm3 molec.-1 s-1 for terpinolene and β-caryophyllene respectively. Mechanistic studies have also been conducted in order to identify and quantify the main reaction products. Total organic nitrates and SOA yields have been determined. Both terpenes appear to be major ON precursors in both gas and particle phases with formation yields of 69 % for terpinolene and 79 % for β-caryophyllene respectively. They are also major SOA precursors, with maximum SOA yields of around 60 % for terpinolene and 90 % for β-caryophyllene. In order to support these observations, chemical analyses of the gas-phase products were performed at the molecular scale using a proton transfer reaction–time-of-flight–mass spectrometer (PTR-ToF-MS) and FTIR. Detected products allowed proposing chemical mechanisms and providing explanations through peroxy and alkoxy reaction pathways.
... For many reactions of atmospheric interest, products have been determined by long-path Fourier transform infrared (FT-IR) absorption spectroscopy in atmospheric simulation chambers used to study reactions at a mechanistic level (Doussin et al., 1997;Glowacki et al., 2007;Nilsson et al., 2009;Seakins, 2010), but this method has relatively poor time resolution compared to direct studies of elementary reactions. Such studies can be influenced by secondary chemistry and wall reactions, which may transform reactive products into more stable species on the timescale of the experiment. ...
The chemistry and reaction kinetics of reactive species dominate changes to the composition of complex chemical systems, including Earth's atmosphere. Laboratory experiments to identify reactive species and their reaction products, and to monitor their reaction kinetics and product yields, are key to our understanding of complex systems. In this work we describe the development and characterisation of an experiment using laser flash photolysis coupled with time-resolved mid-infrared (mid-IR) quantum cascade laser (QCL) absorption spectroscopy, with initial results reported for measurements of the infrared spectrum, kinetics, and product yields for the reaction of the CH2OO Criegee intermediate with SO2. The instrument presented has high spectral (< 0.004 cm-1) and temporal (< 5 µs) resolution and is able to monitor kinetics with a dynamic range to at least 20 000 s-1. Results obtained at 298 K and pressures between 20 and 100 Torr gave a rate coefficient for the reaction of CH2OO with SO2 of (3.83 ± 0.63) × 10-11 cm3 s-1, which compares well to the current IUPAC recommendation of 3.70-0.40+0.45 × 10-11 cm3 s-1. A limit of detection of 4.0 × 10-5, in absorbance terms, can be achieved, which equates to a limit of detection of ∼ 2 × 1011 cm-3 for CH2OO, monitored at 1285.7 cm-1, based on the detection path length of (218 ± 20) cm. Initial results, directly monitoring SO3 at 1388.7 cm-1, demonstrate that SO3 is the reaction product for CH2OO + SO2. The use of mid-IR QCL absorption spectroscopy offers significant advantages over alternative techniques commonly used to determine reaction kinetics, such as laser-induced fluorescence (LIF) or ultraviolet absorption spectroscopy, owing to the greater number of species to which IR measurements can be applied. There are also significant advantages over alternative IR techniques, such as step-scan FT-IR, owing to the coherence and increased intensity and spectral resolution of the QCL source and in terms of cost. The instrument described in this work has potential applications in atmospheric chemistry, astrochemistry, combustion chemistry, and in the monitoring of trace species in industrial processes and medical diagnostics.
... For many reactions of atmospheric interest, products have been determined by long-path Fourier transform infrared (FT-IR) absorption spectroscopy in atmospheric simulation chambers used to study reactions at a mechanistic level (Doussin et al., 1997;Glowacki et al., 2007;Nilsson et al., 2009;Seakins, 2010), but this method has relatively poor time resolution compared 75 to direct studies of elementary reactions. Such studies can be influenced by secondary chemistry and wall reactions which may transform reactive products into more stable species on the timescale of the experiment. ...
The chemistry and reaction kinetics of reactive species dominate changes to the composition of complex chemical systems, including Earth’s atmosphere. Laboratory experiments to identify reactive species and their reaction products, and to monitor their reaction kinetics and product yields, are key to our understanding of complex systems. In this work we describe the development and characterisation of an experiment using laser flash photolysis coupled with time-resolved mid-infrared (mid-IR) quantum cascade laser (QCL) absorption spectroscopy, with initial results reported for measurements of the infrared spectrum, kinetics, and product yields for the reaction of the CH2OO Criegee intermediate with SO2. The instrument presented has high spectral (
... Kinetic experiments were performed in the CSA chamber. It is a 6 meters long -977 L -Pyrex reactor (Doussin et al., 1997) equipped with a homogenization system allowing a mixing time below one minute (Fouqueau et al., 90 2020b). This chamber has been designed for the investigation of gas phase chemistry and is thus equipped with instruments dedicated to gas phase monitoring. ...
Biogenic volatile organic compounds (BVOCs) are subject to an intense emission by forests and crops into the atmosphere. They can rapidly react with the nitrate radical (NO3) during nighttime to form number of functionalized products. Among them, organic nitrates (ON) have been shown to behave as reservoirs of reactive nitrogen and consequently influence the ozone budget and secondary organic aerosols (SOA) which are known to have a direct and indirect effect on the radiative balance, and thus on climate. Nevertheless, BVOCs + NO3 reactions remain poorly understood. Thus, the primary purpose of the follow-up study is to furnish new kinetic and mechanistic data for one monoterpenes (C10H16), terpinolene, and one sesquiterpene (C15H24), β-caryophyllene, using simulation chamber experiments. These two compounds have been chosen in order to fill the lack of experimental data. Rate constants have been measured using both relative and absolute methods. They have been measured to be (5.5 ± 3.8) × 10−11 and (1.7 ± 1.4) × 10−11 cm3 molecule−1 s−1 for terpinolene and β-caryophyllene respectively. Mechanistic studies have also been conducted in order to identify and quantify the main reaction products. Total organic nitrates and SOA yields have been determined. Both terpenes appear to be major ON precursors both in gas and particle phase with formation yields of 69 % for terpinolene and 79 % for β-caryophyllene respectively. They also are major SOA precursor, with maximum SOA yields of around 60 % for both of the compounds. In order to support these observations, chemical analyses of the gas phase products were performed at the molecular scale using PTR-TOF-MS and FTIR. Detected products allowed proposing chemical mechanisms and providing explanations through peroxy and alkoxy reaction pathways.
Nighttime NO 3 ‐initiated oxidation of biogenic volatile organic compounds (BVOCs), such as monoterpenes, plays a crucial role as sources of organic nitrates (ONs) and secondary organic aerosols (SOA), which are known to have significant impacts on climate, air quality, and human health. Nevertheless, these reactions are still poorly understood. Therefore, the primary objective of this study is to provide new kinetic data for two monoterpenes, α‐phellandrene and β‐phellandrene through experiments in simulation chambers. The rate constants have been determined using an absolute kinetic method and found to be (3.9 ± 0.6) × 10 −11 cm ³ molecule ⁻¹ s ⁻¹ for α‐phellandrene and (6.6 ± 1.0) × 10 ⁻¹² cm ³ molecule ⁻¹ s ⁻¹ for β‐phellandrene. These rate constants have been compared to data from the literature. For α‐phellandrene, previous studies were scattered, and this new determination allows us to confirm the lowest value provided by the other absolute rate determination. For β‐phellandrene, our study provides the first absolute rate determination which is in good agreement with the unique value from the literature obtained by the relative rate technique. Rate constants of α‐ and β‐phellandrene are also compared to those of other monoterpenes having similar chemical structures. These kinetic results show that the oxidation by NO 3 is a significant sink of α‐ and β‐phellandrene during nighttime.
Les textiles sont des matériaux à la fois quotidiens, omniprésents dans nos intérieurs, mais aussi de prestige, comme en témoigne leur profusion dans les collections des musées et monuments historiques. La préciosité et l’unicité de ceux-ci nécessitent de les préserver sur des périodes prolongées durant lesquelles l’environnement a un impact déterminant. Ce travail de thèse vise à comprendre le rôle précis de l’environnement d’exposition des textiles dans la dégradation des fibres naturelles qui les composent, et plus particulièrement les mécanismes encore méconnus de dégradation liés à la présence de polluants atmosphériques, gazeux et particulaires.Pour y parvenir, une approche environnementale a été utilisée. Tout d’abord, quatre musées et monuments historiques situés dans des milieux contrastés - urbain (Musée de Cluny, Paris), semi-rural (château de Fontainebleau), marin (musée de la Tapisserie de Bayeux et Villa Kérylos, Beaulieu-sur-Mer) - ont été sélectionnés pour représenter la variété des conditions de conservation des textiles en France. Ces sites ont été étudiés de manière exhaustive (microclimat, concentration en polluants gazeux, granulométrie et chimie des aérosols, morphochimie des particules déposées, vitesse d’empoussièrement) afin de disposer de données environnementales complètes. Certaines pièces des monuments ont également été sélectionnées comme plateformes d’exposition de textiles-modèles (coton, laine et soie) pour un vieillissement naturel.Les données environnementales collectées ont été utilisées pour conditionner des expériences de vieillissement accéléré en laboratoire. La chambre CIME, dédiée à l’étude de l’interaction entre les matériaux et leur environnement, a été utilisée pour reproduire le dépôt sec de particules clés identifiées sur sites (mélange de calcite, argiles, suies, mascagnite et halite) et pour exposer les textiles empoussiérés artificiellement et naturellement à plusieurs polluants gazeux (SO2, NO2, CO2, O3, COV). Les concentrations des espèces gazeuses et les conditions thermo-hygriques ont été choisies en accord avec les mesures effectuées sur site.Ce dispositif expérimental, mettant en parallèle mesures et expositions in-situ avec expériences en laboratoire, a permis de mettre en évidence et de suivre à la fois la réactivité des couches de particules et l’évolution des fibres exposées aux polluants.Le dépôt est le premier à réagir en formant des efflorescences. La croissance de celles-ci peut se faire entre les fibres des textiles. Ces néoformations de sulfates, nitrates et formates se produisent indépendamment de la nature du substrat. Elles peuvent être dommageables pour les textiles car leur emplacement au sein des fibres les rend difficiles à dépoussiérer et ces nouveaux mélanges de sels peuvent avoir des points de déliquescence plus bas, favorisant ainsi la formation de films d’eau.Les fibres sont également altérées par le contact avec les polluants gazeux : le SO2 et l’acide formique mènent à la rupture de liaisons des chaînes polymères du coton et des liaisons peptidiques de la soie, tandis que le NO2 engendre plutôt des oxydations des fibres. Le coton est le plus sensible au NO2 (combinaison de l’oxydation et de l’hydrolyse des fibres). Si l’acide formique attaque la laine en entraînant des ruptures de liaisons covalentes, comme pour les autres fibres naturelles étudiées, cette fibre résiste mieux au SO2 que la soie et semble même être protégée des altérations futures suite à son exposition à ce polluant. Dans tous les cas, les altérations provoquées par les polluants gazeux sont exacerbées en présence de dépôt, quelle que soit sa composition chimique.Cette recherche combinant étude environnementale et simulation réaliste des vieillissements de textiles-modèles met clairement en évidence le caractère non protecteur des particules et la nécessité de limiter leur impact en condition intérieure.
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