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Letteratura scientifica selezionata sul tema "Aqueous aerosols"

Autore: Grafiati

Pubblicato: 25 gennaio 2025

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Articoli di riviste sul tema "Aqueous aerosols"

Beaver, M. R., M. J. Elrod, R. M. Garland e M. A. Tolbert. "Ice nucleation in sulfuric acid/organic aerosols: implications for cirrus cloud formation". Atmospheric Chemistry and Physics Discussions 6, n. 2 (28 marzo 2006): 2059–90. http://dx.doi.org/10.5194/acpd-6-2059-2006.

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Abstract. Using an aerosol flow tube apparatus, we have studied the effects of aliphatic aldehydes (C3 to C10) and ketones (C3 and C9) on ice nucleation in sulfuric acid aerosols. Mixed aerosols were prepared by combining an organic vapor flow with a flow of sulfuric acid aerosols over a small mixing time (~60 s) at room temperature. No acid-catalyzed reactions were observed under these conditions, and physical uptake was responsible for the organic content of the sulfuric acid aerosols. In these experiments, aerosol organic content, determined by a Mie scattering analysis, was found to vary with the partial pressure of organic, the flow tube temperature, and the identity of the organic compound. The physical properties of the organic compounds (primarily the solubility and melting point) were found to play a dominant role in determining the mode of nucleation (homogenous or heterogeneous) and the specific freezing temperatures observed. Overall, very soluble, low-melting organics, such as acetone and propanal, caused a decrease in aerosol ice nucleation temperatures when compared with aqueous sulfuric acid aerosol. In contrast, sulfuric acid particles exposed to organic compounds of eight carbons and greater, of much lower solubility and higher melting temperatures, nucleate ice at temperatures above aqueous sulfuric acid aerosols. Organic compounds of intermediate carbon chain length, C4-C7, (of intermediate solubility and melting temperatures) nucleated ice at the same temperature as aqueous sulfuric acid aerosols. Interpretations and implications of these results for cirrus cloud formation are discussed.

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Beaver, M. R., M. J. Elrod, R. M. Garland e M. A. Tolbert. "Ice nucleation in sulfuric acid/organic aerosols: implications for cirrus cloud formation". Atmospheric Chemistry and Physics 6, n. 11 (4 agosto 2006): 3231–42. http://dx.doi.org/10.5194/acp-6-3231-2006.

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Abstract (sommario):

Abstract. Using an aerosol flow tube apparatus, we have studied the effects of aliphatic aldehydes (C3 to C10) and ketones (C3 and C9) on ice nucleation in sulfuric acid aerosols. Mixed aerosols were prepared by combining an organic vapor flow with a flow of sulfuric acid aerosols over a small mixing time (~60 s) at room temperature. No acid-catalyzed reactions were observed under these conditions, and physical uptake was responsible for the organic content of the sulfuric acid aerosols. In these experiments, aerosol organic content, determined by a Mie scattering analysis, was found to vary with the partial pressure of organic, the flow tube temperature, and the identity of the organic compound. The physical properties of the organic compounds (primarily the solubility and melting point) were found to play a dominant role in determining the inferred mode of nucleation (homogenous or heterogeneous) and the specific freezing temperatures observed. Overall, very soluble, low-melting organics, such as acetone and propanal, caused a decrease in aerosol ice nucleation temperatures when compared with aqueous sulfuric acid aerosol. In contrast, sulfuric acid particles exposed to organic compounds of eight carbons and greater, of much lower solubility and higher melting temperatures, nucleate ice at temperatures above aqueous sulfuric acid aerosols. Organic compounds of intermediate carbon chain length, C4-C7, (of intermediate solubility and melting temperatures) nucleated ice at the same temperature as aqueous sulfuric acid aerosols. Interpretations and implications of these results for cirrus cloud formation are discussed.

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Tsui, William G., Joseph L. Woo e V. Faye McNeill. "Impact of Aerosol-Cloud Cycling on Aqueous Secondary Organic Aerosol Formation". Atmosphere 10, n. 11 (31 ottobre 2019): 666. http://dx.doi.org/10.3390/atmos10110666.

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Chemical processing of organic material in aqueous atmospheric aerosols and cloudwater is known to form secondary organic aerosols (SOA), although the extent to which each of these processes contributes to total aerosol mass is unclear. In this study, we use GAMMA 5.0, a photochemical box model with coupled gas and aqueous-phase chemistry, to consider the impact of aqueous organic reactions in both aqueous aerosols and clouds on isoprene epoxydiol (IEPOX) SOA over a range of pH for both aqueous phases, including cycling between cloud and aerosol within a single simulation. Low pH aqueous aerosol, in the absence of organic coatings or other morphology which may limit uptake of IEPOX, is found to be an efficient source of IEPOX SOA, consistent with previous work. Cloudwater at pH 4 or lower is also found to be a potentially significant source of IEPOX SOA. This phenomenon is primarily attributed to the relatively high uptake of IEPOX to clouds as a result of higher water content in clouds as compared with aerosol. For more acidic cloudwater, the aqueous organic material is comprised primarily of IEPOX SOA and lower-volatility organic acids. Both cloudwater pH and the time of day or sequence of aerosol-to-cloud or cloud-to-aerosol transitions impacted final aqueous SOA mass and composition in the simulations. The potential significance of cloud processing as a contributor to IEPOX SOA production could account for discrepancies between predicted IEPOX SOA mass from atmospheric models and measured ambient IEPOX SOA mass, or observations of IEPOX SOA in locations where mass transfer limitations are expected in aerosol particles.

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Liang, H., Z. M. Chen, D. Huang, Y. Zhao e Z. Y. Li. "Impacts of aerosols on the chemistry of atmospheric trace gases: a case study of peroxides and HO<sub>2</sub> radicals". Atmospheric Chemistry and Physics Discussions 13, n. 6 (20 giugno 2013): 16549–95. http://dx.doi.org/10.5194/acpd-13-16549-2013.

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Abstract. Field measurements of atmospheric peroxides were obtained during the summer on two consecutive years over urban Beijing, and focused on the impacts of aerosols on the chemistry of peroxide compounds and hydroperoxyl radicals (HO2). The major peroxides were determined to be hydrogen peroxide (H2O2), methyl hydroperoxide (MHP), and peroxyacetic acid (PAA). A negative correlation was found between H2O2 and PAA in rainwater, providing evidence for a conversion between H2O2 and PAA in the aqueous phase. A standard gas phase chemistry model based on the NCAR Master Mechanism provided a good reproduction of the observed H2O2 profile on non-haze days but greatly overpredicted the H2O2 level on haze days. We attribute this overprediction to the reactive uptake of HO2 by the aerosols, since there was greatly enhanced aerosol loading and aerosol liquid water content on haze days. The discrepancy between the observed and modeled H2O2 can be diminished by adding to the model a newly proposed transition metal ion catalytic mechanism of HO2 in aqueous aerosols. This confirms the importance of the aerosol uptake of HO2 and the subsequent aqueous phase reactions in the reduction of H2O2. The closure of HO2 and H2O2 between the gas and aerosol phases suggests that the aerosols do not have a net reactive uptake of H2O2, because the conversion of HO2 to H2O2 on aerosols compensates for the H2O2 loss. Laboratory studies for the aerosol uptake of H2O2 in the presence of HO2 are urgently required to better understand the aerosol uptake of H2O2 in the real atmosphere.

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Liang, H., Z. M. Chen, D. Huang, Y. Zhao e Z. Y. Li. "Impacts of aerosols on the chemistry of atmospheric trace gases: a case study of peroxides and HO<sub>2</sub> radicals". Atmospheric Chemistry and Physics 13, n. 22 (20 novembre 2013): 11259–76. http://dx.doi.org/10.5194/acp-13-11259-2013.

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Abstract (sommario):

Abstract. Field measurements of atmospheric peroxides were obtained during the summer on two consecutive years over urban Beijing, which highlighted the impacts of aerosols on the chemistry of peroxide compounds and hydroperoxyl radicals (HO2). The major peroxides were determined to be hydrogen peroxide (H2O2), methyl hydroperoxide (MHP), and peroxyacetic acid (PAA). A negative correlation was found between H2O2 and PAA in rainwater, providing evidence for a conversion between H2O2 and PAA in the aqueous phase. A standard gas phase chemistry model based on the NCAR Master Mechanism provided a good reproduction of the observed H2O2 profile on non-haze days but greatly overpredicted the H2O2 level on haze days. We attribute this overprediction to the reactive uptake of HO2 by the aerosols, since there was greatly enhanced aerosol loading and aerosol liquid water content on haze days. The discrepancy between the observed and modeled H2O2 can be diminished by adding to the model a newly proposed transition metal ion catalytic mechanism of HO2 in aqueous aerosols. This confirms the importance of the aerosol uptake of HO2 and the subsequent aqueous phase reactions in the reduction of H2O2. The closure of HO2 and H2O2 between the gas and aerosol phases suggests that the aerosols do not have a net reactive uptake of H2O2, because the conversion of HO2 to H2O2 on aerosols compensates for the H2O2 loss. Laboratory studies for the aerosol uptake of H2O2 in the presence of HO2 are urgently required to better understand the aerosol uptake of H2O2 in the real atmosphere.

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Morand, Gabriel, Pascale Chevallier, Cédric Guyon, Michael Tatoulian e Diego Mantovani. "In-Situ One-Step Direct Loading of Agents in Poly(acrylic acid) Coating Deposited by Aerosol-Assisted Open-Air Plasma". Polymers 13, n. 12 (10 giugno 2021): 1931. http://dx.doi.org/10.3390/polym13121931.

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In biomaterials and biotechnology, coatings loaded with bioactive agents are used to trigger biological responses by acting as drug release platforms and modulating surface properties. In this work, direct deposition of poly(acrylic acid) coatings containing various agents, such as dyes, fluorescent molecules, was achieved by aerosol-assisted open-air plasma. Using an original precursors injection strategy, an acrylic acid aerosol was loaded with an aqueous aerosol and deposited on silicon wafers. Results clearly showed that agents dissolved in the aqueous aerosol were successfully entrapped in the final coating. The effect of aerosols concentration, flow rate, and treatment time, on the coating morphology and the amount of entrapped agents, was also investigated. It was demonstrated that this process has the potential to entrap a tunable amount of any sensible water-soluble agent without altering its activity. To the best of our knowledge, this is the first time that the loading of an aqueous aerosol in coatings deposited by plasma from a liquid aerosol precursor is reported. This innovative approach complements plasma deposition of coatings loaded with bioactive agents from aqueous aerosols with the use of non-volatile liquid precursors.

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Wilson, T. W., B. J. Murray, R. Wagner, O. Möhler, H. Saathoff, M. Schnaiter, J. Skrotzki et al. "Glassy aerosols with a range of compositions nucleate ice heterogeneously at cirrus temperatures". Atmospheric Chemistry and Physics Discussions 12, n. 4 (10 aprile 2012): 8979–9033. http://dx.doi.org/10.5194/acpd-12-8979-2012.

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Abstract. Atmospheric secondary organic aerosol (SOA) is likely to exist in an ultra viscous or glassy state, particularly at low temperatures and humidities. It has also been shown that glassy aqueous citric acid aerosol is able to nucleate ice heterogeneously under conditions relevant to cirrus in the tropical tropopause layer (TTL). In this study we test if glassy aerosols with a range of chemical compositions heterogeneously nucleate ice under cirrus conditions. Three single component aqueous solution aerosols (raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA) and levoglucosan) and one multi component aqueous solution aerosol (raffinose mixed with five dicarboxylic acids and ammonium sulphate) were studied in both the liquid and glassy states at a large cloud simulation chamber. The investigated organic compounds have similar functionality to oxidised organic material found in atmospheric aerosol and have estimated temperature/humidity induced glass transition thresholds that fall within the range predicted for atmospheric SOA. All the aerosols tested were found to nucleate ice heterogeneously in the deposition mode at temperatures relevant to the TTL (<200 K). Raffinose and HMMA, which form glasses at higher temperatures, nucleated ice heterogeneously at temperatures as high as 214.6 and 218.5 K respectively. We present the calculated ice active surface site density, ns, of the aerosols tested here and also of glassy citric acid aerosol as a function of relative humidity with respect to ice (RHi). We also propose a parameterisation which can be used to estimate heterogeneous ice nucleation by glassy aerosol for use in cirrus cloud models up to ~220 K. Finally, we show that heterogeneous nucleation by glassy aerosol may compete with ice nucleation on mineral dust particles in mid-latitudes cirrus.

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Ge, Xinlei, Qi Zhang, Yele Sun, Christopher R. Ruehl e Ari Setyan. "Effect of aqueous-phase processing on aerosol chemistry and size distributions in Fresno, California, during wintertime". Environmental Chemistry 9, n. 3 (2012): 221. http://dx.doi.org/10.1071/en11168.

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Environmental contextAqueous-phase processes in fogs and clouds can significantly alter atmospheric fine particles with consequences for climate and human health. We studied the influence of fog and rain on atmospheric aerosol properties, and show that aqueous-phase reactions contribute to the production of secondary aerosol species and change significantly the composition and microphysical properties of aerosols. In contrast, rains effectively remove aerosols and reduce their concentrations. AbstractSubmicrometre aerosols (PM1) were characterised in situ with a high resolution time-of-flight aerosol mass spectrometer and a scanning mobility particle sizer in Fresno, CA, from 9 to 23 January 2010. Three dense fog events occurred during the first week of the campaign whereas the last week was influenced by frequent rain events. We thus studied the effects of aqueous-phase processing on aerosol properties by examining the temporal variations of submicrometre aerosol composition and size distributions. Rains removed secondary species effectively, leading to low loadings of PM1 dominated by primary organic species. Fog episodes, however, increased the concentrations of secondary aerosol species (sulfate, nitrate, ammonium and oxygenated organic aerosol). The size distributions of these secondary species, which always showed a droplet mode peaking at ~500 nm in the vacuum aerodynamic diameter, increased in mode size during fog episodes as well. In addition, the oxygen-to-carbon ratio of oxygenated organic species increased in foggy days, indicating that fog processing likely enhances the production of secondary organic aerosol as well as its oxidation degree. Overall, our observations show that aqueous-phase processes significantly affect submicrometre aerosol chemistry and microphysics in the Central Valley of California during winter, responsible for the production of secondary inorganic and organic aerosol species and the formation of droplet mode particles, thus altering the climatic and health effects of ambient aerosols in this region.

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Woo, J. L., e V. F. McNeill. "simpleGAMMA – a reduced model of secondary organic aerosol formation in the aqueous aerosol phase (aaSOA)". Geoscientific Model Development Discussions 8, n. 1 (22 gennaio 2015): 463–82. http://dx.doi.org/10.5194/gmdd-8-463-2015.

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Abstract. There is increasing evidence that the uptake and aqueous processing of water-soluble volatile organic compounds (VOCs) by wet aerosols or cloud droplets is an important source of secondary organic aerosol (SOA). We recently developed GAMMA (Gas–Aerosol Model for Mechanism Analysis), a zero-dimensional kinetic model that couples gas-phase and detailed aqueous-phase atmospheric chemistry for speciated prediction of SOA and organosulfate formation in cloudwater or aqueous aerosols. Results from GAMMA simulations of SOA formation in aerosol water (McNeill et al., 2012) indicate that it is dominated by two pathways: isoprene epoxydiol (IEPOX) uptake followed by ring-opening chemistry (under low-NOx conditions) and glyoxal uptake. This suggested that it is possible to model the majority of aqueous aerosol phase SOA mass using a highly simplified reaction scheme. We have therefore developed a reduced version of GAMMA, simpleGAMMA. Close agreement in predicted aaSOA mass is observed between simpleGAMMA and GAMMA under all conditions tested (between pH 1–4 and RH 40–80%) after 12 h of simulation. simpleGAMMA is computationally efficient and suitable for coupling with larger-scale atmospheric chemistry models.

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Lim, Y. B., e B. J. Turpin. "Laboratory evidence of organic peroxide and peroxyhemiacetal formation in the aqueous phase and implications for aqueous OH". Atmospheric Chemistry and Physics 15, n. 22 (19 novembre 2015): 12867–77. http://dx.doi.org/10.5194/acp-15-12867-2015.

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Abstract. Aqueous chemistry in atmospheric waters (e.g., cloud droplets or wet aerosols) is considered a potentially important atmospheric pathway to produce secondary organic aerosol (SOAaq). Water-soluble organic compounds with small carbon numbers (C2–C3) are precursors for SOAaq; products include organic acids, organic sulfates, and high-molecular-weight compounds/oligomers. Fenton reactions and the uptake of gas-phase OH radicals are considered to be the major oxidant sources for aqueous organic chemistry. However, the sources and availability of oxidants in atmospheric waters are not well understood. The degree to which OH is produced in the aqueous phase affects the balance of radical and non-radical aqueous chemistry, the properties of the resulting aerosol, and likely its atmospheric behavior. This paper demonstrates organic peroxide formation during aqueous photooxidation of methylglyoxal using ultra-high-resolution Fourier transform ion cyclotron resonance electrospray ionization mass spectrometry (FTICR-MS). Organic peroxides are known to form through gas-phase oxidation of volatile organic compounds. They contribute secondary organic aerosol (SOA) formation directly by forming peroxyhemiacetals and epoxides (i.e., IEPOX), and indirectly by enhancing gas-phase oxidation through OH recycling. We provide simulation results of organic peroxide/peroxyhemiacetal formation in clouds and wet aerosols and discuss organic peroxides as a source of condensed-phase OH radicals and as a contributor to aqueous SOA.

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Più fonti

Tesi sul tema "Aqueous aerosols"

Petersen-Sonn, Emma Amalie. "Tropospheric triplet state chemistry in aqueous aerosols". Electronic Thesis or Diss., Lyon 1, 2024. http://www.theses.fr/2024LYO10239.

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Récemment, les états triplets des espèces organiques ont attiré l'attention en tant qu'oxydants potentiellement importants dans les environnements aqueux, en concurrence avec l'oxygène singulet et les radicaux OH. Tout d'abord, la thèse étudie des extraits d'échantillons d'aérosols, en hiver et en été, pour leurs concentrations à l'état d'équilibre et les rendements quantiques des trois principaux oxydants : les états triplets, l'oxygène singulet et les radicaux OH. Nos résultats montrent que si l'on considère à la fois les concentrations à l'état d'équilibre et les constantes de vitesse du second ordre pour les oxydants avec différentes classes d'espèces organiques, les états triplets seront dans la plupart des cas l'oxydant dominant. La thèse présente également les résultats préliminaires d'une étude en collaboration qui examine les méthodes de normalisation des mesures du rendement quantique de l'oxygène singulet. L'étude suivante de cette thèse a porté sur l'examen de la composition massique de l'un des échantillons d'aérosol. Cet échantillon a été analysé par spectrométrie de masse à haute résolution avant et après son irradiation. Les principaux résultats montrent qu'au cours du vieillissement, des espèces plus importantes se sont formées. Un substitut, la vanilline, a été choisi pour étudier les voies de dégradation des espèces d'aérosols et a montré un grand nombre de produits après l'irradiation. L'effet de l'irradiation de la vanilline à 6 degree C a montré une augmentation de la quantité d'espèces avec des nombres de carbone plus importants, tels que les espèces C23. Les espèces C23 ont été attribuées à des trimères de vanilline. Enfin, la production de radicaux OH à partir d'espèces à l'état triplet a été étudiée en phase aqueuse. La formation d'OH à partir de sources connues de radicaux OH, NO3- et H2O2, a été comparée à celle de la vanilline et du 4-hydroxybenzaldéhyde, qui ont été utilisés comme indicateurs des espèces organiques présentes dans les aérosols aqueux (et les nuages/brouillards). Une étude bibliographique des concentrations des sources d'OH dans les aérosols et les nuages/brouillards a été compilée et utilisée en combinaison avec les taux de formation d'OH. A partir de ces estimations, il est clair que les états triplets pourraient potentiellement avoir des taux de formation d'OH qui sont de 1 à 2 ordres de grandeur plus élevés que NO3- et H2O2. Dans l'ensemble, cette thèse fournit des résultats qui illustrent l'importance des états triplets dans les aérosols aqueux, et le fait qu'ils peuvent être sous-estimés en tant qu'oxydants pour les espèces organiques et en tant que sources de radicaux OH
Recently, triplet states of organic species have gained attention as oxidants that are potentially important in aqueous environments, competing with singlet oxygen and OH radicals. Firstly, the thesis investigates extracts of aerosol samples, from winter and summer time, for their steady-state concentrations and quantum yields of the three main oxidants: triplet states, singlet oxygen, and OH radicals. Our findings show that when considering both steady-state concentrations and second-order rate constants for the oxidants with various classes of organic species, the triplet states will in most cases be the dominant oxidant. The thesis also show preliminary results of a collaborating study that investigates methods for standardizing singlet oxygen quantum yield measurements. The next study of this thesis involved the examination of the mass composition of one of the aerosol samples. This sample was analyzed using high resolution mass spectrometry before and after the sample was irradiated. Main results show that during aging larger species were formed. A proxy, vanillin, was chosen to investigate the degradation pathways of aerosol species, and showed a large number of products after irradiation. The effect of irradiating vanillin at 6 degree C showed an increased amount of species with larger carbon numbers, such as C23 species. The C23 species were attributed to trimers of vanillin. Lastly, the OH radical production from triplet state species were investigated in the aqueous phase. The OH formation from known sources of OH radicals, NO3- and H2O2, were compared to that of vanillin and 4-hydroxybenzaldehyde, which were applied for proxies of organic species present in aqueous aerosols (and clouds/fog). A literature study of concentrations of the OH sources in aerosols and cloud/fog was compiled and used in combination with the OH formation rates. From these estimations, it was clear that triplet states could potentially have OH formation rates that are 1-2 orders of magnitude larger than NO3- and H2O2. Overall, this thesis provides results that illustrates the importance of triplet states in the aqueous aerosols, and that they may be underestimated as both oxidants for organic species and as sources of OH radicals

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ROVELLI, GRAZIA. "Characterizing the hygroscopic properties of aerosols: from binary aqueous systems to atmospheric aerosols". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2016. http://hdl.handle.net/10281/104639.

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The quantification of the hygroscopic properties of atmospheric aerosols is important to understand several processes they are involved in, such as clouds formation, their interaction with solar radiation and the penetration of particles in the human respiratory track. In addition, the interaction of deposited aerosols with surfaces depends on their physical state, too; thus, characterizing their phase transitions as a function of their chemical composition is key to understanding the effects they have on materials (e.g. printed circuits, cultural heritage artifacts). In order to investigate the hygroscopic properties of aerosols, an electrical conductance method in an Aerosol Exposure Chamber was developed for the determination of the phase transitions of PM2.5 aerosol samples during relative humidity cycles. The obtained Deliquescence and Crystallization Relative Humidity (DRH and CRH) were put in relation with the ionic chemical composition of the analyzed samples: it was found that seasonal chemical variations result in seasonal trends for DRH and CRH, too. The implications of these results for Free-Cooled Data Centers, for the understanding of the role of particles in stone-decay processes of cultural heritage artifacts and for the common algorithms used in the remote sensing of particulate matter concentrations were evaluated. The ionic fraction characterisation was also used as an input for a state-of-the-art equilibrium aerosol model (E-AIM) to simulate the DRH of the samples. Some discrepancies were evidenced in the comparison of experimental and modelled values, because the hygroscopic properties of the organic components need to be included too. In order to effectively account for their contribute, current aerosol models need to be refined with accurate hygroscopicity measurements on organic compounds of increasing molecular complexity and their mixtures with common electrolytes. Such measurements are essential for understanding and modelling the microphysical properties that determine the partitioning of water between the gas and the aerosol phases in chemically complex systems. In this context, an experimental technique based on evaporation kinetics measurements in an Cylindrical Electrodynamic Balance was developed for the measurement of hygroscopic properties on single confined droplets from aqueous solutions with known chemical composition. To expand the range of applicability of a previously developed technique to water activities from 0.5 to values close to saturation (>0.99), well-characterized binary and ternary inorganic mixtures were considered. The obtained results were used to successfully validate this technique by comparing them with calculations from E-AIM model and to assess the sensitivity of this technique to small changes in chemical composition. The first class of atmospherically relevant compounds that was considered was aminium sulphates, which are the products of the neutralization reactions of sulphuric acid and short-chained alkylamines (methyl- and ethylamines). They have been detected in atmospheric aerosols up to hundreds of pg m-3, but their hygroscopic behaviour was less characterized than their inorganic equivalent, ammonium sulphate, even if they can promote cloud droplets formation and particle growth.

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Clegg, S. L. "The atmospheric chemistry of extremely concentrated solutions". Thesis, University of East Anglia, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376080.

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Phipps, Paul R. (Paul Robert). "Characterisation and pulmonary deposition of therapeutic and diagnostic aqueous aerosols". Phd thesis, Department of Pharmacy, 1990. http://hdl.handle.net/2123/6645.

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Adkins, Carol Leslie Jones Seinfeld John H. Flagan Richard C. "Use of a continuous stirred tank reactor for the study of aqueous aerosol chemistry". Diss., Pasadena, Calif. : California Institute of Technology, 1988. http://resolver.caltech.edu/CaltechTHESIS:12042009-080025691.

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Thesis (Ph. D.)--California Institute of Technology, 1988. UM #88-03,381.
Advisor names found in the Acknowledgments pages of the thesis. Title from home page. Viewed 02/19/2010. Includes bibliographical references.

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Buajarern, Jariya. "Fundamental studies of inorganic and organic aqueous aerosols using optical tweezers". Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439956.

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Xia, Shasha. "CROSS PHOTOREACTION OF PYRUVIC AND GLYOXYLIC ACIDS IN MODEL AQUEOUS AEROSOLS". UKnowledge, 2014. https://uknowledge.uky.edu/chemistry_etds/42.

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Abstract (sommario):

Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. Aerosols from natural and anthropogenic sources can be primary organic aerosols (POA), which are directly emitted to the atmosphere, or secondary organic aerosols (SOA) that are formed from chemical reactions of gas-phase precursors. At variance with the well investigated formation of SOA from gas phase precursors, the chemistry of aqueous SOAs that contribute to the total SOA budget remains unknown. Field measurements have revealed that carboxylic, dicarboxylic and oxocarboxylic acids are abundant species present in SOAs. This thesis explores the fate of two such acids, pyruvic (PA) and glyoxylic (GA) acids surrogates of the oxocarboxylic acids in the atmosphere, in their cross reaction under solar irradiation and dark thermal aging. Mixtures of complex photoproducts are identified by ion chromatography (IC) with conductivity and electrospray (ESI) mass spectrometry (MS) detection, direct ESI-MS analysis in the negative ion mode, and nuclear magnetic resonance spectroscopy (NMR) analysis including one-dimensional (1H- and 13C-NMR) and two-dimensional techniques such as gradient correlation spectroscopy (gCOSY) and heteronuclear single quantum correlation (HSQC). A reaction mechanism for the cross reaction is provided based on all experimental observations.

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Zuba, Leonard P. "Preparation of mixed-metal catalysts from non-aqueous solutions via an aerosol process". Morgantown, W. Va. : [West Virginia University Libraries], 1998. http://etd.wvu.edu/templates/showETD.cfm?recnum=108.

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Thesis (M.S.)--West Virginia University, 1998.
Title from document title page. Document formatted into pages; contains xii, 136 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 131-132).

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Peckhaus, Andreas [Verfasser], e Thomas [Akademischer Betreuer] Leisner. "Study of phase transitions in atmospheric aerosols: freezing and efflorescence of complex aqueous mixtures / Andreas Peckhaus ; Betreuer: Thomas Leisner". Heidelberg : Universitätsbibliothek Heidelberg, 2016. http://d-nb.info/1180616502/34.

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Price, Hannah Clare. "Diffusion within aqueous atmospheric aerosol". Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/9164/.

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Atmospheric aerosol particles influence our planet's climate and contribute to poor air quality, increased mortality and degraded visibility. Central to these issues is how atmospheric aerosol particles interact with gas species to affect chemistry and cloud formation. Recent research shows that some aqueous solutions relevant to atmospheric aerosol (notably secondary organic material, which constitutes a large mass fraction of atmospheric aerosol particles) can be highly viscous and can behave mechanically like a solid. This has led to suggestions that these particles exist out of equilibrium with the gas phase in the atmosphere, with implications for heterogeneous chemistry and ice nucleation. In order to quantify any kinetic limitations, it is vital to have quantitative data about the diffusion of various relevant species within these materials. This thesis describes the direct measurement and application of water diffusion coefficients in aqueous solutions relevant to atmospheric aerosol, including sucrose and secondary organic material. A water diffusion model is developed, validated and used with a new parameterisation of the water diffusion coefficient in secondary organic material to quantify the rate of uptake and loss of water from aerosol particles. It is shown that, although this material can behave mechanically like a solid, at 280 K water diffusion is not kinetically limited on timescales of 1 s for atmospheric-sized particles. This is not the case, however, for colder conditions: modelling of 100 nm particles predicts that under mid to upper tropospheric conditions radial inhomogeneities in water content produce a low viscosity surface region and more solid interior. This may significantly affect aerosol chemistry and the ability of particles to nucleate ice. Also reported are the diffusion coefficients of sucrose in aqueous sucrose at higher concentrations than have been previously investigated. These measurements provide insights into the role of organic molecules in aerosol evaporation and chemistry. Together with the diffusion coefficients of water measured in this material, they will also offer a valuable means to study the fundamental nature of diffusion in a simple but widely used material, and specifically the breakdown of the Stokes-Einstein relationship.

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Libri sul tema "Aqueous aerosols"

Woo, Joseph L. Gas-Aerosol Model For Mechanism Analysis: Kinetic Prediction Of Gas- And Aqueous-Phase Chemistry Of Atmospheric Aerosols. [New York, N.Y.?]: [publisher not identified], 2014.

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Tsui, William Gang. Simulating Aqueous Secondary Organic Aerosol Formation and Cloudwater Chemistry in Gas-Aerosol Model for Mechanism Analysis. [New York, N.Y.?]: [publisher not identified], 2020.

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Capitoli di libri sul tema "Aqueous aerosols"

Marcolli, C., T. Peter, B. Zobrist e Thomas Koop. "Heterogeneous Ice Nucleation of Aqueous Solutions with Immersed Mineral Dust Particles". In Nucleation and Atmospheric Aerosols, 461–65. Dordrecht: Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-6475-3_92.

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Böttcher, Markus, e Thomas Koop. "Immersion Freezing in Emulsifi ed Aqueous Sulfuric Acid Solutions Containing AgI Particles". In Nucleation and Atmospheric Aerosols, 466–70. Dordrecht: Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-6475-3_93.

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Murray, Benjamin J., e Allan K. Bertram. "Strong Dependence of Cubic Ice Formation on Aqueous Droplet Ammonium to Sulphate Ratio". In Nucleation and Atmospheric Aerosols, 432–35. Dordrecht: Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-6475-3_86.

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Jungwirth, Pavel. "Physical Properties and Atmospheric Reactivity of Aqueous Sea Salt Micro-Aerosols". In Water in Confining Geometries, 277–93. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-662-05231-0_13.

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De Haan, David O. "Aqueous Aerosol Processing of Glyoxal and Methylglyoxal: Recent Measurements of Uptake Coefficients, SOA Production, and Brown Carbon Formation". In ACS Symposium Series, 149–67. Washington, DC: American Chemical Society, 2018. http://dx.doi.org/10.1021/bk-2018-1299.ch008.

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Finlay, Warren H. "Aqueous aerosol delivery devices". In The Mechanics of Inhaled Pharmaceutical Aerosols, 183–212. Elsevier, 2019. http://dx.doi.org/10.1016/b978-0-08-102749-3.00008-7.

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"Chapter 5 Bulk aqueous phase chemistry relevant to cloud droplets". In Atmospheric Aerosol Chemistry, 177–202. De Gruyter, 2022. http://dx.doi.org/10.1515/9781501519376-005.

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Atti di convegni sul tema "Aqueous aerosols"

Hrahsheh, Fawaz, e Gerald Wilemski. "Fluctuating structure of aqueous organic nanodroplets". In NUCLEATION AND ATMOSPHERIC AEROSOLS: 19th International Conference. AIP, 2013. http://dx.doi.org/10.1063/1.4803204.

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Pathak, H., B. Wyslouzil, A. Obeidat e G. Wilemski. "The structure of aqueous-alkane nanodroplets". In NUCLEATION AND ATMOSPHERIC AEROSOLS: 19th International Conference. AIP, 2013. http://dx.doi.org/10.1063/1.4803307.

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Koop, Thomas. "The formation of ice clouds from supercooled aqueous aerosols". In The 15th international conference on nucleation and atmospheric aerosols. AIP, 2000. http://dx.doi.org/10.1063/1.1361928.

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Fisenko, Sergey P., e Julia A. Khodyko. "Evaporative cooling, nucleation and nanoparticles coalescence in femtoliter droplet of aqueous solution". In NUCLEATION AND ATMOSPHERIC AEROSOLS: 19th International Conference. AIP, 2013. http://dx.doi.org/10.1063/1.4803217.

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Crljenica, Ivica, Taina Yli-Juuti, Alessandro A. Zardini, Jan Julin, Merete Bilde e Ilona Riipinen. "Determining the saturation vapour pressures of keto-dicarboxylic acids in aqueous solutions". In NUCLEATION AND ATMOSPHERIC AEROSOLS: 19th International Conference. AIP, 2013. http://dx.doi.org/10.1063/1.4803306.

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Tauer, Klaus. "A universal tool to investigate nucleation from aqueous solutions". In The 15th international conference on nucleation and atmospheric aerosols. AIP, 2000. http://dx.doi.org/10.1063/1.1361900.

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Alofs, Darryl J. "A critique of homogeneous freezing measurements of aqueous sulfuric acid". In The 15th international conference on nucleation and atmospheric aerosols. AIP, 2000. http://dx.doi.org/10.1063/1.1361898.

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Marley, Nancy, e Jeffrey Gaffney. "Evaluating the long-wave radiative forcing of aqueous atmospheric aerosols". In Intersociety Energy Conversion Engineering Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1994. http://dx.doi.org/10.2514/6.1994-4150.

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Lappas, Petros, Daniel R. Haylett, Jason M. Porter, David F. Davidson, Jay B. Jeffries, Ronald K. Hanson, Leslie A. Hokama e Kristien E. Mortelmans. "Destruction of Bacterial-Spore-Laden Aqueous Aerosols in Shock-Heated Flows". In Biomedical Optics. Washington, D.C.: OSA, 2008. http://dx.doi.org/10.1364/biomed.2008.jma28.

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Tolstonogova, Yuliya S., Alexandr Mayor, Sergey Golik e Vladimir Lisitsa. "Features of the formation of emission spectra excited by femtosecond radiation in aqueous aerosols". In Optical Sensing and Detection VI, a cura di Francis Berghmans e Anna G. Mignani. SPIE, 2020. http://dx.doi.org/10.1117/12.2555275.

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Rapporti di organizzazioni sul tema "Aqueous aerosols"

Gaffney, J. S., e N. A. Marley. Longwave radiative forcing by aqueous aerosols. Office of Scientific and Technical Information (OSTI), gennaio 1995. http://dx.doi.org/10.2172/72917.

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Gaffney, J. S., N. A. Marley e M. M. Cunningham. Climate missing links: Aqueous greenhouse species in clouds, fogs and aerosols. Office of Scientific and Technical Information (OSTI), novembre 1991. http://dx.doi.org/10.2172/10184731.

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