115 results on '"Bilde, M."'
Search Results
2. Investigating the effect of temperature and time on the starvation of lubricants for the wind turbine industry.
- Author
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Georgiou, E. P., Drees, D., Lopes, L. M., De Bilde, M., and Koutsomichalis, A.
- Subjects
WIND turbines ,TEMPERATURE effect ,STARVATION ,GLOBAL warming ,LUBRICATION & lubricants - Abstract
In the wind turbine industry, mechanical components sometimes have to operate under starved lubrication. This occurs mainly after maintenance and/or repairing procedures, when the wind turbine is starting up again after a prolonged inactive period. In field observations have shown that oil starvation is more prominent in warmer climates and of course for longer durations where the mechanical components remained 'inactive'. To get a better insight on this issue, a validation test procedure was developed based on reciprocating sliding tests. This protocol was used to investigate the starvation behaviour of two commercially available oils on metallic components, which were exposed at different temperatures (ranging from −20° to 40°C) and durations (ranging from 5 to 21 days). Based on these tests the resistance to starvation (failure time) and the effect of critical waiting time and temperature to initiate starvation were assessed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Expanding the applicability of ASTM D3233A Pin & Vee Block method to evaluate lubricant emulsions for cutting applications.
- Author
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Georgiou, E.P., Drees, D., Helmetag, K., Van der Donck, T., Lopes, L.M., Semal, F., De Bilde, M., and Anderson, M.
- Subjects
CUTTING fluids ,STANDARDIZED tests ,METALLURGY ,LUBRICATION & lubricants ,TORQUE - Abstract
ASTM Method D3233A uses a Pin&Vee Block tester to evaluate cutting fluids. However, the standard defines a steel-steel contact, uses a small volume of lubricant, and the test report is limited to the 'ultimate failure load'. With our approach, we bring testing closer to reality, using different metallurgies and testing the oils in aqueous emulsion-form. We monitor the frictional torque throughout increasing load, so that differences between products are revealed that are not visible in failure load alone. By modifying lubrication to recirculated or misted conditions, we simulate cutting of forming operations. Consequently, this provides an additional tool for cost efficient ranking of cutting fluids, based on an industry-accepted instrument. We demonstrate same ranking of cutting fluids as well established Tapping Torque Tests, with the advantage of using a simplified and lower cost configuration. Developing a standardized test protocol involves more work on reproducibility and correlation to real machining processes. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Can We Put a Value on the Adhesion and Tackiness of Greases?
- Author
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Georgiou, E. P., Drees, D., De Bilde, M., and Anderson, M.
- Published
- 2018
- Full Text
- View/download PDF
5. Chemical properties of HULIS from three different environments
- Author
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Kristensen, T. B., Du, L., Nguyen, Q. T., Nøjgaard, J. K., Koch, C. Bender, Nielsen, O. Faurskov, Hallar, A. G., Lowenthal, D. H., Nekat, B., Pinxteren, D. van, Herrmann, H., Glasius, M., Kjaergaard, H. G., and Bilde, M.
- Published
- 2015
- Full Text
- View/download PDF
6. Primary BIOlogical Aerosol in the ATmosphere: origins, microphysical processes, and climatic feedbacks (BIOAAT) project
- Author
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Sahyoun, M., Ervens, B., Tsigaridis, K., Santl-Temkiv, T., Finster, K., Bilde, M., Kanakidou, M., Im, U., Institut de Chimie de Clermont-Ferrand (ICCF), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national polytechnique Clermont Auvergne (INP Clermont Auvergne), Université Clermont Auvergne (UCA)-Université Clermont Auvergne (UCA), and Bonnefoy, Stéphanie
- Subjects
[CHIM] Chemical Sciences ,[CHIM]Chemical Sciences ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2021
7. Evaporation of ternary inorganic/organic aqueous droplets: Sodium chloride, succinic acid and water
- Author
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Zardini, A.A., Riipinen, I., Koponen, I.K., Kulmala, M., and Bilde, M.
- Published
- 2010
- Full Text
- View/download PDF
8. The ice-nucleating activity of Arctic sea surface microlayer samples and marine algal cultures
- Author
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Ickes, L, Porter, GCE, Wagner, R, Adams, MP, Bierbauer, S, Bertram, AK, Bilde, M, Christiansen, S, Ekman, AML, Gorokhova, E, Höhler, K, Kiselev, AA, Leck, C, Möhler, O, Murray, BJ, Schiebel, T, Ullrich, R, and Salter, ME
- Subjects
Earth sciences ,Arctic ,Ice nucleation ,ddc:550 ,Aerosol - Abstract
In recent years, sea spray as well as the biological material it contains has received increased attention as a source of ice-nucleating particles (INPs). Such INPs may play a role in remote marine regions, where other sources of INPs are scarce or absent. In the Arctic, these INPs can influence water–ice partitioning in low-level clouds and thereby the cloud lifetime, with consequences for the surface energy budget, sea ice formation and melt, and climate. Marine aerosol is of a diverse nature, so identifying sources of INPs is challenging. One fraction of marine bioaerosol (phytoplankton and their exudates) has been a particular focus of marine INP research. In our study we attempt to address three main questions. Firstly, we compare the ice-nucleating ability of two common phytoplankton species with Arctic seawater microlayer samples using the same instrumentation to see if these phytoplankton species produce ice-nucleating material with sufficient activity to account for the ice nucleation observed in Arctic microlayer samples. We present the first measurements of the ice-nucleating ability of two predominant phytoplankton species: Melosira arctica, a common Arctic diatom species, and Skeletonema marinoi, a ubiquitous diatom species across oceans worldwide. To determine the potential effect of nutrient conditions and characteristics of the algal culture, such as the amount of organic carbon associated with algal cells, on the ice nucleation activity, Skeletonema marinoi was grown under different nutrient regimes. From comparison of the ice nucleation data of the algal cultures to those obtained from a range of sea surface microlayer (SML) samples obtained during three different field expeditions to the Arctic (ACCACIA, NETCARE, and ASCOS), we found that they were not as ice active as the investigated microlayer samples, although these diatoms do produce ice-nucleating material. Secondly, to improve our understanding of local Arctic marine sources as atmospheric INPs we applied two aerosolization techniques to analyse the ice-nucleating ability of aerosolized microlayer and algal samples. The aerosols were generated either by direct nebulization of the undiluted bulk solutions or by the addition of the samples to a sea spray simulation chamber filled with artificial seawater. The latter method generates aerosol particles using a plunging jet to mimic the process of oceanic wave breaking. We observed that the aerosols produced using this approach can be ice active, indicating that the ice-nucleating material in seawater can indeed transfer to the aerosol phase. Thirdly, we attempted to measure ice nucleation activity across the entire temperature range relevant for mixed-phase clouds using a suite of ice nucleation measurement techniques – an expansion cloud chamber, a continuous-flow diffusion chamber, and a cold stage. In order to compare the measurements made using the different instruments, we have normalized the data in relation to the mass of salt present in the nascent sea spray aerosol. At temperatures above 248 K some of the SML samples were very effective at nucleating ice, but there was substantial variability between the different samples. In contrast, there was much less variability between samples below 248 K. We discuss our results in the context of aerosol–cloud interactions in the Arctic with a focus on furthering our understanding of which INP types may be important in the Arctic atmosphere.
- Published
- 2020
9. A method for determining thermophysical properties of organic material in aqueous solutions: Succinic acid
- Author
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Riipinen, I., Svenningsson, B., Bilde, M., Gaman, A., Lehtinen, K.E.J., and Kulmala, M.
- Published
- 2006
- Full Text
- View/download PDF
10. Kinetics and mechanism of the reaction of CI atoms with nitrobenzene
- Author
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Frasig, L., Nielsen, O.J., Bilde, M., Wallington, T.J., Orlando, J.J., and Tyndall, G.S.
- Subjects
Fourier transform infrared spectroscopy -- Usage ,Chlorine -- Chemical properties ,Nitrobenzenes -- Chemical properties ,Chemicals, plastics and rubber industries - Abstract
Smog chamber/FTIR techniques were used to study the kinetics and mechanism of the reaction of Cl atoms with nitrobenzene in 10-700 Torr of N2. The UV-visible spectrums of C6H5N(O)2 were measured.
- Published
- 2000
11. Evaporation of methyl- and dimethyl-substituted malonic, succinic, glutaric and adipic acid particles at ambient temperatures
- Author
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Mønster, J., Rosenørn, T., Svenningsson, B., and Bilde, M.
- Published
- 2004
- Full Text
- View/download PDF
12. Pre-screening of hydraulic fluids for vane pumps: An alternative to Vickers vane pump tests
- Author
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Georgiou, E.P., Drees, D., De Bilde, M., and Anderson, M.
- Published
- 2018
- Full Text
- View/download PDF
13. First year of research activities at Villum Research Station, Station Nord, North Greenland
- Author
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Henrik Skov, Rossana Bossi, Andreas Massling, Jacob Klenø Nøjgaard, Ingeborg Elbæk Nielsen, Nguyen, Q. T., Katrin Vorkamp, Robert Lange, Maria Bech Poulsen, Jesper Heile Christensen, Kaj Mantzius Hansen, Bilde, M., Glasius, M., Sørensen, S. B., Tina Santl-Temkiv, Kai Finster, Pilgaard, S., Lise Lotte Sørensen, Jensen, J. K., and Jesper Baldtzer Liisberg
- Published
- 2016
14. Atmospheric oxidation mechanism of methyl formate
- Author
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Wallington, T.J., Hurley, M.D., Maurer, T., Barnes, I., Becker, K.H., Tyndall, G.S., Orlando, J.J., Pimentel, A.S., and Bilde, M.
- Subjects
Chlorine compounds -- Research ,Oxidation-reduction reaction -- Research ,Nitrogen oxide -- Research ,Potassium compounds -- Research ,Chemicals, plastics and rubber industries - Abstract
Three different FTIR smog chamber technique is used to characterize the products formed due to Cl atom initiated oxidation of methyl formate in 700-760 Torr of air in the presence and absence of NO(sub x) at (296 plusmn 2) K. The reaction mechanism of atmospheric oxidation of methyl formate is described in detail together with the kinetic measurements.
- Published
- 2001
15. Characterization of humic-like substances in Arctic aerosols
- Author
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Nguyen, Q. T., Kristensen, T. B., Hansen, A. M. K., Skov, H., Bossi, R., Massling, A., Sorensen, L. L., Bilde, M., Glasius, M., and Nojgaard, J. K.
- Subjects
HULIS Arctic brown carbon light absorption aerosol mass SOLUBLE ORGANIC-COMPOUNDS TANDEM MASS-SPECTROMETRY SIZE-EXCLUSION CHROMATOGRAPHY MOLECULAR-WEIGHT DISTRIBUTION FINE ATMOSPHERIC AEROSOL BIOMASS-BURNING AEROSOLS ELECTROSPRAY-IONIZATION CHEMICAL-COMPOSITION OPTICAL-PROPERTIES FULVIC-ACIDS - Abstract
Humic-like substances (HULIS) are a complex group of relatively high molecular weight organic compounds which contribute considerably to the mass of organic carbon (OC) and influence the light-absorbing properties of aerosols. In this work, HULIS were investigated for the first time in the high-Arctic atmosphere, focusing on the chemical characterization and mass contribution of HULIS to the total suspended particle (TSP) mass using weekly aerosol samples collected at Station Nord, northeast Greenland every fourth week during 2010. Average HULIS-C concentration was 11ng C m(-3) during the darker months (November-April) and 4ng C m(-3) during the other months (May-October) with an annual mass concentration of 0.020.01 mu gm(-3). HULIS-C contributed to 3-16% of water-soluble organic carbon (WSOC), whereas HULIS accounted for 0.7-4.1% of TSP mass, with TSP typically below 1.0 mu gm(-3). Concentrations of OC, WSOC, HULIS, selected HULIS functional groups (carboxylic acids, aromatic carboxylic acids, and organosulfates) and levoglucosan overlapped with the typical Arctic haze pattern with elevated concentrations during winter to early spring. The aromatic carboxylic acid portion accounted for a larger share of total carboxylic acid of HULIS during the darker months (7%) compared to the brighter months (3%). The more abundant aromatic carboxylic acid functional groups and the moderate correlation between HULIS and levoglucosan concentrations during the darker months both indicate that biomass burning aerosols and thereby emissions of aromatic compounds could contribute to HULIS in the Arctic, especially during late winter. During the brighter months, relatively higher average molecular weight of HULIS was observed.
- Published
- 2014
16. BINARY EVAPORATION OF SUCCINIC ACID AND WATER DROPLETS: COMPARISON OF SIMULATED AND EXPERIMENTAL RESULTS
- Author
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RIIPINEN, I., LEHTINEN, K.E.J., SVENNINGSSON, B., BILDE, M., and KULMALA, M.
- Published
- 2004
- Full Text
- View/download PDF
17. EVAPORARTION RATES AND VAPOUR PRESSURES OF SUCCINIC ACID SOLUTION DROPLETS
- Author
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SVENNINGSSON, B., BILDE, M., RIIPINEN, I., LEHTINEN, K.E.J., and KULMALA, M.
- Published
- 2004
- Full Text
- View/download PDF
18. Formation and occurrence of dimer esters of pinene oxidation products in atmospheric aerosols
- Author
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Glasius, M., Rosenoern, T., Surratt, J. D., Bilde, M., and Goldstein, A. H.
- Abstract
The formation of carboxylic acids and dimer esters from α-pinene oxidation was investigated in a smog chamber and in ambient aerosol samples collected during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX). Chamber experiments of α-pinene ozonolysis in dry air and at low NOx concentrations demonstrated formation of two dimer esters, pinyl-diaterpenyl (MW 358) and pinonyl-pinyl dimer ester (MW 368), under both low- and high-temperature conditions. Concentration levels of the pinyl-diaterpenyl dimer ester were lower than the assumed first-generation oxidation products cis-pinic and terpenylic acids, but similar to the second-generation oxidation products 3-methyl-1,2,3-butane tricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). Dimer esters were observed within the first 30 min, indicating rapid production simultaneous to their structural precursors. However, the sampling time resolution precluded conclusive evidence regarding formation from gas- or particle-phase processes. CCN activities of the particles formed in the smog chamber displayed a modest variation during the course of experiments, with κ values in the range 0.06–0.09 (derived at a supersaturation of 0.19%). The pinyl-diaterpenyl dimer ester was also observed in ambient aerosol samples collected above a ponderosa pine forest in the Sierra Nevada Mountains of California during two seasonally distinct field campaigns in September 2007 and July 2009. The pinonyl-pinyl ester was observed for the first time in ambient air during the 2009 campaign, and although present at much lower concentrations, it was correlated with the abundance of the pinyl-diaterpenyl ester, suggesting similarities in their formation. The maximum concentration of the pinyl-diaterpenyl ester was almost 10 times higher during the warmer 2009 campaign relative to 2007, while the concentration of cis-pinic acid was approximately the same during both periods, and lack of correlation with levels of cis-pinic and terpenylic acids for both campaigns indicate that the formation of the pinyl-diaterpenyl ester was not controlled by their ambient abundance. In 2009 the concentration of the pinyl-diaterpenyl ester was well correlated with the concentration of DTAA, a supposed precursor of diaterpenylic acid, suggesting that the formation of pinyl-diaterpenyl dimer was closely related to DTAA. Generally, the pinyl-diaterpenyl ester was found at higher concentrations under higher temperature conditions, both in the smog-chamber study and in ambient air aerosol samples, and exhibited much higher conce
- Published
- 2013
- Full Text
- View/download PDF
19. The effect of sub-zero temperature on the formation and composition of secondary organic aerosol from ozonolysis of alpha-pinene.
- Author
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Kristensen, K., Jensen, L. N., Glasius, M., and Bilde, M.
- Abstract
This study presents a newly constructed temperature controlled cold-room smog chamber at Aarhus University, Denmark. The chamber is herein utilized to study the effect of sub-zero temperature on the formation and chemical composition of secondary organic aerosol (SOA) from ozone initiated oxidation of α-pinene. The chemical composition of α-pinene SOA formed from dark ozonolysis of α-pinene at 293 K and 258 K was investigated using High-Resolution Time-of-Flight Aerosol Mass Spectrometry (HR-ToF-AMS) and Ultra-High Performance Liquid Chromatography/Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry (UHPLC/ESI-qToF-MS). For comparison, an OH-initiated oxidation experiment was performed at 293 K. In ozonolysis experiments it was found that oxygen-to-carbon (O : C) ratios were higher in the particles formed at 293 K compared to 258 K. A total of 16 different organic acids and 30 dimers esters were quantified in the collected particles composing up to 34% of the total α-pinene SOA mass with increased mass fraction of carboxylic acids in particles from α-pinene ozonolysis at 258 K compared to 293 K. In contrast, dimer esters showed suppressed formation at the sub-zero reaction temperature, thus contributing 3% to SOA mass at 258 K while contributing 9% at 293 K. SOA formed in the OH-initiated oxidation of α-pinene at 293 K resulted in low concentrations of dimer esters supporting Criegee intermediates as a possible pathway to dimer ester formation. Vapour pressure estimates of the identified carboxylic acids and dimer esters are presented and show how otherwise semi-volatile carboxylic acids at sufficiently low temperatures may classify as low or even extremely low volatile organic compounds (ELVOC), thus may add to an enhanced particle formation observed at the sub-zero temperature through gas-to-particle conversion. The change in chemical composition of the SOA particles with temperature is ascribed to a combination of effects: the decreased vapour pressures and hence increased condensation of carboxylic acids from the gas phase to the particle phase along with suppressed formation of the high molecular weight dimer esters and different gas and particle phase chemistry results in particles of different chemical composition as a consequence of low reaction temperatures. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
20. Investigating primary marine aerosol properties: CCN activity of sea salt and mixed inorganic-organic particles
- Author
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King, S.M., Butcher, A.C., Rosenoern, T., Coz, E., Lieke, K.I., Leeuw, G. de, Nilsson, E.D., and Bilde, M.
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Urban Development ,Earth & Environment ,CAS - Climate, Air and Sustainability ,Environment ,Built Environment ,EELS - Earth, Environmental and Life Sciences - Abstract
Sea spray particles ejected as a result of bubbles bursting from artificial seawater containing salt and organic matter in a stainless steel tank were sampled for size distribution, morphology, and cloud condensation nucleus (CCN) activity. Bubbles were generated either by aeration through a diffuser or by water jet impingement on the seawater surface. Three objectives were addressed in this study. First, CCN activities of NaCl and two types of artificial sea salt containing only inorganic components were measured to establish a baseline for further measurements of mixed organic-inorganic particles. Second, the effect of varying bubble residence time in the bulk seawater solution on particle size and CCN activity was investigated and was found to be insignificant for the organic compounds studied. Finally, CCN activities of particles produced from jet impingement were compared with those produced from diffuser aeration. Analyses indicate a considerable amount of organic enrichment in the jet-produced particles relative to the bulk seawater composition when sodium laurate, an organic surfactant, is present in the seawater. In this case, the production of a thick foam layer during impingement may explain the difference in activation and supports hypotheses that particle production from the two methods of generating bubbles is not equal. © 2012 American Chemical Society.
- Published
- 2012
21. Intercomparison of cloud condensation nuclei and hygroscopic fraction the LACIS Experiment in November (LExNo)
- Author
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Snider, J.R., Wex, H., Dusek, U., Frank, G.P., Kiendler-Scharr, A., Mentel, T. F., Petters, M.D., Pöschl, U., Rose, D., Kristensson, A., Stratmann, F., Henning, T., Henning, S., Kiselev, A., Bilde, M., and Burkhart, M.
- Subjects
ddc:550 - Abstract
Four cloud condensation nuclei (CCN) instruments were used to sample size-selected particles prepared at the Leipzig Aerosol Cloud Interaction Simulator facility. Included were two Wyoming static diffusion CCN instruments, the continuous flow instrument built by Droplet Measurement Technologies, and the continuous flow Leipzig instrument. The aerosols were composed of ammonium sulfate, levoglucosan, levoglucosan and soot, and ammonium hydrogen sulfate and soot. Comparisons are made among critical supersaturation values from the CCN instruments and derived from measurements made with a humidified tandem differential mobility system. The comparison is quite encouraging: with few exceptions the reported critical supersaturations agree within known experimental uncertainty limits. Also reported are CCN- and hygroscopicity-based estimates of the soot particles' solute fraction. Relative differences between these are as large as 40%, but an error analysis demonstrates that agreement within experimental uncertainty is achieved. We also analyze data from the Droplet Measurement Technologies and the two Wyoming static diffusion instruments for evidence of size distribution broadening and investigate levoglucosan particle growth kinetics in the Wyoming CCN instrument.
- Published
- 2010
22. DMPS/SMPS intercomparison in terms of particle sizing:Reports on BACCI activities
- Author
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Massling, Andreas, Löndahl, J., Swietlicki, E., Ketzel, Matthias, Jensen, M., Wåhlin, Peter, Bilde, M., Kristensson, M., Hansson, H.-C., Ströhm, J., Jonsson, A., Hallquist, M., and Lunder, C.
- Published
- 2006
23. Particulate PAH concentrations in Copenhagen, Denmark
- Author
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Mønster, J. G., Glasius, M., Bossi, R., Bilde, M., Nielsen, O. J., and Palmgren, F.
- Published
- 2005
24. Indoor and Outdoor Particle Measurements in a Street Canyon in Copenhagen
- Author
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Wåhlin, P., Palmgren, F., Afshari, A., Gunnarsen, L., Nielsen, O. J., Bilde, M., and Kildesø, J.
- Subjects
indoor pm10 ,penetration efficiency ,deposition rate ,indoor traffic particles - Published
- 2002
25. On the seawater temperature dependence of the sea spray aerosol generated by a continuous plunging jet.
- Author
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Salter, M. E., Nilsson, E. D., Butcher, A., and Bilde, M.
- Published
- 2014
- Full Text
- View/download PDF
26. Hygroscopicity, CCN and volatility properties of submicron atmospheric aerosol in a boreal forest environment during the summer of 2010.
- Author
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Hong, J., Häkkinen, S. A. K., Paramonov, M., Äijälä, M., Hakala, J., Nieminen, T., Mikkilä, J., Prisle, N. L., Kulmala, M., Riipinen, I., Bilde, M., Kerminen, V.-M., and Petäjä, T.
- Subjects
CONDENSATION (Meteorology) ,EVAPORATION (Meteorology) ,ATMOSPHERIC aerosols ,TAIGAS ,SOOT ,SUMMER - Abstract
A Volatility-Hygroscopicity Tandem Differential Mobility Analyzer (VH-TDMA) was applied to study the hygroscopicity and volatility properties of submicron atmospheric aerosol particles in a boreal forest environment in Hyytiälä, Finland during the summer of 2010. Aitken and accumulation mode internally mixed particles (50 nm, 75 nm and 110 nm in diameter) were investigated. Hygroscopicity was found to increase with particle size. The relative mass fraction of organics and SO
4 2- is probably the major contributor to the fluctuation of the hygroscopicity for all particle sizes. The Cloud Condensation Nuclei Counter (CCNC)-derived hygroscopicity parameter κ was observed to be slightly higher than κ calculated from VH-TDMA data under sub-saturated conditions, potential reasons for this behavior are discussed shortly. Also, the size-resolved volatility properties of particles were investigated. Upon heating, more small particles evaporated compared to large particles. There was a significant amount of aerosol volume (non-volatile material) left, even at heating temperatures of 280 °C. Using size resolved volatility-hygroscopicity analysis, we concluded that there was always hygroscopic material remaining in the particles at different heating temperatures, even at 280 °C. This indicates that the observed non-volatile aerosol material did not consist solely of black carbon. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
27. Hygroscopicity, CCN and volatility properties of submicron atmospheric aerosol in a boreal forest environment during the summer of 2010.
- Author
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Hong, J., Häkkinen, S. A. K., Paramonov, M., Äijälä, M., Hakala, J., Nieminen, T., Mikkilä, J., Prisle, N., Kulmala, M., Riipinen, I., Bilde, M., Kerminen, V.-M., and Petäjä, T.
- Abstract
The Volatility-Hygroscopicity Tandem Differential Mobility Analyzer (VH-TDMA) was applied to study the hygroscopicity and volatility properties of submicron atmospheric aerosol in a boreal forest environment in Hyytiälä, Finland during the summer of 2010. Aitken and accumulation mode particles (50 nm, 75nm and 110 nm) were investigated. The results suggest that the particles were internally mixed at all sizes. Hygroscopicity was found to increase with size. The relative mass fraction of organics and SO
4 2- is probably the major contributor to the fluctuation of the hygroscopicity for all particle sizes. The Cloud Condensation Nuclei counter (CCNc)-derived hygroscopicity parameter κ was slightly higher than κ calculated from VH-TDMA data under sub-saturated conditions, which can be explained by the fact that particulate organics have a different degree of dissolution in sub- and supersaturated conditions. Also, the size-resolved volatility properties of particles were investigated. Upon heating, small particles evaporated more compared to large particles. There was a significant amount of aerosol volume (non-volatile material) left even at heating temperatures above 280 °C. Using size resolved volatility-hygroscopicity analysis, we concluded that there was always hygroscopic material remaining in the particles of different sizes at all different heating temperatures, even above 280 κC. This indicates that the observed non-volatile aerosol material was not consisting solely of black carbon. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
28. Formation and occurrence of dimer esters of pinene oxidation products in atmospheric aerosols.
- Author
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Kristensen, K., Enggrob, K. L., King, S. M., Worton, D. R., Platt, S. M., Mortensen, R., Rosenoern, T., Surratt, J. D., Bilde, M., Goldstein, A. H., and Glasius, M.
- Subjects
ATMOSPHERIC aerosols ,DIMERS ,ESTERS ,PINENE ,OXIDATION ,BIOSPHERE ,ACETATES - Abstract
The formation of carboxylic acids and dimer esters from -pinene oxidation was investigated in a smog chamber and in ambient aerosol samples collected during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX). Chamber experiments of -pinene ozonolysis in dry air and at low NOx concentrations demonstrated formation of two dimer esters, pinyl-diaterpenyl (MW 358) and pinonyl-pinyl dimer ester (MW 368), under both lowand high-temperature conditions. Concentration levels of the pinyl-diaterpenyl dimer ester were lower than the assumed first-generation oxidation products cis-pinic and terpenylic acids, but similar to the second-generation oxidation products 3-methyl-1,2,3-butane tricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). Dimer esters were observed within the first 30 min, indicating rapid production simultaneous to their structural precursors. However, the sampling time resolution precluded conclusive evidence regarding formation from gas- or particle-phase processes. CCN activities of the particles formed in the smog chamber displayed a modest variation during the course of experiments, with k values in the range 0.06-0.09 (derived at a supersaturation of 0.19%). The pinyl-diaterpenyl dimer ester was also observed in ambient aerosol samples collected above a ponderosa pine forest in the Sierra Nevada Mountains of California during two seasonally distinct field campaigns in September 2007 and July 2009. The pinonyl-pinyl ester was observed for the first time in ambient air during the 2009 campaign, and although present at much lower concentrations, it was correlated with the abundance of the pinyl-diaterpenyl ester, suggesting similarities in their formation. The maximum concentration of the pinyl-diaterpenyl ester was almost 10 times higher during the warmer 2009 campaign relative to 2007, while the concentration of cis-pinic acid was approximately the same during both periods, and lack of correlation with levels of cis-pinic and terpenylic acids for both campaigns indicate that the formation of the pinyl-diaterpenyl ester was not controlled by their ambient abundance. In 2009 the concentration of the pinyl-diaterpenyl ester was well correlated with the concentration of DTAA, a supposed precursor of diaterpenylic acid, suggesting that the formation of pinyl-diaterpenyl dimer was closely related to DTAA. Generally, the pinyl-diaterpenyl ester was found at higher concentrations under higher temperature conditions, both in the smog-chamber study and in ambient air aerosol samples, and exhibited much higher concentrations at night relative to daytime in line with previous results. We conclude that analysis of pinyl dimer esters provides valuable information on pinene oxidation processes and should be included in studies of formation and photochemical aging of biogenic secondary organic aerosols, especially at high temperatures. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
29. CCN activity and volatility of β-caryophyllene secondary organic aerosol.
- Author
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Frosch, M., Bilde, M., Nenes, A., Praplan, A. P., Jurányi, Z., Dommen, J., Gysel, M., Weingartner, E., and Baltensperger, U.
- Subjects
CARYOPHYLLENE ,CLOUDS ,CONDENSATION ,ATMOSPHERIC aerosols ,ATMOSPHERIC chemistry ,EXPERIMENTS ,OZONOLYSIS - Abstract
In a series of smog chamber experiments, the cloud condensation nuclei (CCN) activity of secondary organic aerosol (SOA) generated from ozonolysis of β-caryophyllene was characterized by determining the CCN derived hygroscopicity parameter, ΚCCN, from experimental data. Two types of CCN counters, operating at different temperatures, were used. The effect of semi-volatile organic compounds on the CCN activity of SOA was studied using a thermodenuder. Overall, SOA was only slightly CCN active (with ΚCCN in the range 0.001-0.16), and in dark experiments with no OH scavenger present, ΚCCN decreased when particles were sent through the thermodenuder (with a temperature up to 50 °C). SOA was generated under different experimental conditions: In some experiments, an OH scavenger (2-butanol) was added. SOA from these experiments was less CCN active than SOA produced in experiments without an OH scavenger (i.e. where OH was produced during ozonolysis). In other experiments, lights were turned on, either without or with the addition of HONO (OH source). This led to the formation of more CCN active SOA. SOA was aged up to 30 h through exposure to ozone and (in experiments with no OH scavenger present) to OH. In all experiments, the derived ΚCCN consistently increased with time after initial injection of β-caryophyllene, showing that chemical ageing increases the CCN activity of β-caryophyllene SOA. ΚCCN was also observed to depend on supersaturation, which was explained either as an evaporation artifact from semi-volatile SOA (only observed in experiments lacking light exposure) or, alternatively, by effects related to chemical composition depending on dry particle size. Using the method of Threshold Droplet Growth Analysis it was also concluded that the activation kinetics of the SOA do not differ significantly from calibration ammonium sulphate aerosol for particles aged for several hours. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
30. Formation and occurrence of dimer esters of pinene oxidation products in atmospheric aerosols.
- Author
-
Kristensen, K., Enggrob, K. L., King, S. M., Worton, D. R., Platt, S. M., Mortensen, R., Rosenoern, T., Surratt, J. D., Bilde, M., Goldstein, A. H., and Glasius, M.
- Abstract
Formation of carboxylic acids and dimer esters from α-pinene oxidation were investigated in a smog chamber and in ambient aerosol samples collected during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX). Chamber experiments of α-pinene ozonolysis in dry air and at low NO
x concentrations demonstrated formation of two dimer esters, pinyl-diaterpenyl (MW 358) and pinonyl-pinyl dimer ester (MW 368), under both low and high temperature conditions. Concentration levels of the pinyl-diaterpenyl dimer ester were lower than the assumed first-generation oxidation products cis-pinic and terpenylic acids, but similar to the second- generation oxidation products 3-methyl-1,2,3-butane tricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). Dimer esters were observed within the first 30min, indicating rapid production simultaneous to their structural precursors. However, the sampling time resolution precluded conclusive evidence regarding formation from gas- or particle-phase processes. CCN activities of the particles formed in the smog chamber displayed a modest variation during the course of experiments with κ values in the range 0.06-0.09 (derived at a supersaturation of 0.19%). The pinyl-diaterpenyl dimer ester was also observed in ambient aerosol samples collected above a ponderosa pine forest in the Sierra Nevada Mountains of California during two seasonally distinct field campaigns in September 2007 and July 2009. The pinonyl-pinyl ester was observed for the first time in ambient air during the 2009 campaign, and although present at much lower concentrations, it was correlated with the abundance of the pinyl-diaterpenyl ester suggesting similarities in their formation. The maximum concentration of the pinyl-diaterpenyl ester was almost 10 times higher during the warmer 2009 campaign relative to 2007, while the concentration of cis-pinic acid was approximately the same during both periods, and lack of correlation with levels of of cis-pinic and terpenylic acids for both campaigns indicate that the formation of the pinyl-diaterpenyl ester was not controlled by their ambient abundance. In 2009, the concentration of the pinyl-diaterpenyl ester was well correlated with the concentration of DTAA, a supposed precursor of diaterpenylic acid, suggesting that the formation of pinyl-diaterpenyl dimer was closely related to DTAA. Generally, the pinyl-diaterpenyl ester was found at higher concentrations under higher temperature conditions both in the smog-chamber study and in ambient air aerosol samples, and exhibited much higher concentrations at night relative to day-time in line with previous results. We conclude that analysis of pinyl dimer esters provides valuable information on pinene oxidation processes and should be included in studies of formation and photochemical aging of biogenic secondary organic aerosols, especially at high temperatures. [ABSTRACT FROM AUTHOR]- Published
- 2012
- Full Text
- View/download PDF
31. CCN activity and volatility of β-caryophyllene secondary organic aerosol.
- Author
-
Frosch, M., Bilde, M., Nenes, A., Praplan, A. P., Jurányi, Z., Dommen, J., Gysel, M., Weingartner, E., and Baltensperger, U.
- Abstract
In a series of smog chamber experiments, the Cloud Condensation Nuclei (CCN) activity of Secondary Organic Aerosol (SOA) generated from ozonolysis of β-caryophyllene was characterized by determining the CCN derived hygroscopicity parameter, κ
CCN , from experimental data. Two types of CCN counters, operating at different temperatures, were used. The effect of semi-volatile organic compounds on the CCN activity of SOA was studied using a thermodenuder. Overall, SOA was only slightly CCN active (with κCCN in the range 0.001-0.16), and in dark experiments with no OH scavenger present, κCCN decreased when particles were sent through the thermodenuder (with a temperature up to 50 °C). SOA was generated under different experimental conditions: in some experiments, an OH scavenger (2-butanol) was added. SOA from these experiments was less CCN active than SOA produced in experiments without an OH scavenger (i.e. where OH was produced during ozonolysis). In other experiments, lights were turned on, either without or with the addition of HONO (OH source). This led to the formation of more CCN active SOA. SOA was aged up to 30 h through exposure to ozone and (in experiments with no OH scavenger present) to OH. In all experiments, the derived κCCN consistently increased with time after initial injection of β-caryophyllene, showing that chemical ageing increases the CCN activity of β-caryophyllene SOA. κCCN was also observed to depend on supersaturation, which was explained either as an evaporation artifact from semi-volatile SOA (only observed in experiments lacking light exposure) or, alternatively, by effects related to chemical composition depending on dry particle size. Using the method of Threshold Droplet Growth Analysis it was also concluded that the activation kinetics of the SOA do not differ significantly from calibration ammonium sulphate aerosol. [ABSTRACT FROM AUTHOR]- Published
- 2012
- Full Text
- View/download PDF
32. Relating cloud condensation nuclei activity and oxidation level of α-pinene secondary organic aerosols.
- Author
-
Frosch, M., Bilde, M., DeCarlo, P. F., Jurányi, Z., Tritscher, T., Dommen, J., Donahue, N. M., Gysel, M., Weingartner, E., and Baltensperger, U.
- Published
- 2011
- Full Text
- View/download PDF
33. Joint effect of organic acids and inorganic salts on cloud droplet activation.
- Author
-
Frosch, M., Prisle, N. L., Bilde, M., Varga, Z., and Kiss, G.
- Subjects
CLOUDS ,ORGANIC acids ,INORGANIC compounds ,SALT ,FULVIC acids ,SOLUBILITY ,AMMONIUM sulfate - Abstract
We have investigated CCN properties of internally mixed particles composed of one organic acid (oxalic acid dihydrate, succinic acid, adipic acid, citric acid, cis-pinonic acid, or Nordic reference fulvic acid) and one inorganic salt (sodium chloride or ammonium sulphate). Surface tension and water activity of aqueous model solutions with concentrations relevant for CCN activation were measured using a tensiometer and osmometry, respectively. The measurements were used to calculate Köhler curves and critical supersaturations, which were compared to measured critical supersaturations of particles with the same chemical compositions, determined with a cloud condensation nucleus counter. Surfactant surface partitioning was not accounted for. For the aqueous solutions containing cis-pinonic acid and fulvic acid, a depression of surface tension was observed, but for the remaining solutions the effect on surface tension was negligible at concentrations relevant for cloud droplet activation. The surface tension depression of aqueous solutions containing both organic acid and inorganic salt was approximately the same as or smaller than that of aqueous solutions containing the same mass of the corresponding pure organic acids. Water activity was found to be highly dependent on the type and amount of inorganic salt. Sodium chloride was able to decrease water activity more than ammonium sulphate and both inorganic salts are predicted to have a smaller Raoult term than the studied organic acids. Increasing the mass ratio of the inorganic salt led to a decrease in water activity. Water activity measurements were compared to results from the E-AIM model and values estimated from both constant and variable van't Hoff factors. The correspondence between measurements and estimates was overall good, except for highly concentrated solutions. Critical supersaturations calculated with Köhler theory based on measured water activity and surface tension, but not accounting for surface partitioning, compared well with measurements, except for the solutions containing sodium chloride and oxalic acid or one of the more surface active organic compounds. In such cases, significantly lower values were obtained from Köhler theory than the measured critical supersaturations with deviations above 50% for a 60 nm particle containing 50% (dry mass) of Nordic reference fulvic acid, suggesting that surfactant partitioning and/or an effect of sodium chloride on solubility of the organic component is important. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
34. Thermodynamic properties and cloud droplet activation of a series of oxo-acids.
- Author
-
Frosch, M., Zardini, A. A., Platt, S. M., Müller, L., Reinnig, M.-C., Hoffmann, T., and Bilde, M.
- Subjects
OXO compounds ,DICARBOXYLIC acids ,THERMODYNAMICS ,METEOROLOGICAL precipitation ,VAPOR pressure - Abstract
We have investigated the thermodynamic properties of four aliphatic oxo-dicarboyxlic acids identified or thought to be present in atmospheric particulate matter: oxosuccinic acid, 2-oxoglutaric acid, 3-oxoglutaric acid, and 4-oxopimelic acid. The compounds were characterized in terms of their cloud condensation nuclei (CCN) activity, vapor pressure, density, and tendency to decarboxylate in aqueous solution. We deployed a variety of experimental techniques and instruments: a CCN counter, a Tandem Differential Mobililty Analyzer (TDMA) coupled with a laminar flow-tube, and liquid chromatography/mass spectrometry (LC/MS). The presence of the oxo functional group in the α-position causes the vapor pressure of the compounds to diminish by an order of magnitude with respect to the parent dicarboxylic acid, while the CCN activity is similar or increased. Dicarboxylic acids with an oxo-group in the β- position decarboxylate in aqueous solution. We studied the effects of this process on our measurements and findings. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
35. Joint effect of organic acids and inorganic salts on cloud droplet activation.
- Author
-
Frosch, M., Prisle, N. L., Bilde, M., Varga, Z., and Kiss, G.
- Abstract
We have investigated CCN properties of internally mixed particles composed of one organic acid (oxalic acid, succinic acid, adipic acid, citric acid, cis-pinonic acid, or nordic reference fulvic acid) and one inorganic salt (sodium chloride or ammonium sulphate). Surface tension and water activity of aqueous model solutions with concentrations relevant for CCN activation were measured using a tensiometer and osmometry, respectively. The measurements were used to calculate Köhler curves, which were compared to measured critical supersaturations of particles with the same chemical compositions, determined with a cloud condensation nucleus counter. Surfactant surface partitioning was not accounted for. For the mixtures containing cis-pinonic acid or fulvic acid, a depression of surface tension was observed, but for the remaining mixtures the effect on surface tension was negligle at concentrations relevant for cloud droplet activation, and water activity was the more significant term in the Köhler equation. The surface tension depression of aqueous solutions containing both organic acid and inorganic salt was approximately the same as or smaller than that of aqueous solutions containing the same mass of the corresponding pure organic acids. Water activity was found to be highly dependent on the type and amount of inorganic salt. Sodium chloride was able to decrease water activity more than ammonium sulphate and both inorganic compounds had a higher effect on water activity than the studied organic acids, and increasing the mass ratio of the inorganic compound led to a decrease in water activity. Water activity measurements were compared to results from the E-AIM model and values estimated from both constant and variable van't Hoff factors to evaluate the performance of these approaches. The correspondence between measuments and estimates was overall good, except for highly concentrated solutions. Critical supersaturations calculated with Köhler theory based on measured water activity and surface tension, but not accounting for surface partitioning, compared well with measurements, except for the solutions containing sodium chloride or one of the more surface active organic compounds. In such cases, significantly lower values were obtained from Köhler theory than the measured critical supersaturations, suggesting that surfactant partitioning and/or an effect of sodium chloride on solubility of the organic component is important. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
36. Surfactants in cloud droplet activation: mixed organic-inorganic particles.
- Author
-
Prisle, N. L., Raatikainen, T., Laaksonen, A., and Bilde, M.
- Subjects
SURFACE active agents ,ORGANIC compounds ,ATMOSPHERIC aerosols ,SALT ,SURFACE tension - Abstract
Organic compounds with surfactant properties are commonly found in atmospheric aerosol particles. Surface activity can significantly influence the cloud droplet forming ability of these particles. We have studied the cloud droplet formation by two-component particles comprising one of the organic surfactants sodium octanoate, sodium decanoate, sodium dodecanoate, and sodium dodecyl sulfate, mixed with sodium chloride. Critical supersaturations were measured with a static diffusion cloud condensation nucleus counter (Wyoming CCNC-100B). Results were modeled from Köhler theory applying three different representations of surfactant properties in terms of surfactant surface partitioning and reduced droplet surface tension. We here confirm previous results for single-component organic surfactant particles, that experimental critical supersaturations are greatly underpredicted, if reduced surface tension is used while ignoring the effects of surface partitioning in droplets. Furthermore, disregarding surfactant properties by ignoring surface partitioning and assuming the constant surface tension of pure water can also lead to significant underpredictions of experimental critical supersaturations. For the mixed particles comprising less than 50% by mass of surfactant, this approach however still provides a good description of the observed droplet activation. A comprehensive account for surfactant properties, including both surface tension reduction and effects of surface partitioning in activating droplets, generally predicts experimental critical supersaturations well. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
37. Hygroscopic properties of Amazonian biomass burning and European background HULIS and investigation of their effects on surface tension with two models linking H-TDMA to CCNC data.
- Author
-
Fors, E. O., Rissler, J., Massling, A., Svenningsson, B., Andreae, M. O., Dusek, U., Frank, G. P., Hoffer, A., Bilde, M., Kiss, G., Janitsek, S., Henning, S., Facchini, M. C., Decesari, S., and Swietlicki, E.
- Subjects
ATMOSPHERIC aerosols ,HUMIC acid ,ORGANIC acids ,HUMIDITY - Abstract
HUmic-LIke Substances (HULIS) have been identified as major contributors to the organic carbon in atmospheric aerosol. The term "HULIS" is used to describe the organic material found in aerosol particles that resembles the humic organic material in rivers and sea water and in soils. In this study, two sets of filter samples from atmospheric aerosols were collected at different sites. One set of samples was collected at the K-puszta rural site in Hungary, about 80 km SE of Budapest, and a second was collected at a site in Rondônia, Amazonia, Brazil, during the Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Smoke Aerosols, Clouds, Rainfall and Climate (LBA-SMOCC) biomass burning season experiment. HULIS were extracted from the samples and their hygroscopic properties were studied using a Hygroscopicity Tandem Differential Mobility Analyzer (H-TDMA) at relative humidity (RH) <100%, and a cloud condensation nucleus counter (CCNC) at RH >100%. The H-TDMA measurements were carried out at a dry diameter of 100 nm and for RH ranging from 30 to 98%. At 90% RH the HULIS samples showed diameter growth factors between 1.04 and 1.07, reaching values of 1.4 at 98% RH. The cloud nucleating properties of the two sets of aerosol samples were analysed using two types of thermal static cloud condensation nucleus counters. Two different parameterization models were applied to investigate the potential effect of HULIS surface activity, both yielding similar results. For the K-puszta winter HULIS sample, the surface tension at the point of activation was estimated to be lowered by between 34% (47.7 mN/m) and 31% (50.3 mN/m) for dry sizes between 50 and 120 nm in comparison to pure water. A moderate lowering was also observed for the entire water soluble aerosol sample, including both organic and inorganic compounds, where the surface tension was decreased by between 2% (71.2 mN/m) and 13% (63.3 mN/m). [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
38. Intercomparison of cloud condensation nuclei and hygroscopic fraction measurements: Coated soot particles investigated during the LACIS Experiment in November (LExNo).
- Author
-
Snider, J. R., Wex, H., Rose, D., Kristensson, A., Stratmann, F., Hennig, T., Henning, S., Kiselev, A., Bilde, M., Burkhart, M., Dusek, U., Frank, G. P., Kiendler-Scharr, A., Mentel, T. F., Petters, M. D., and Pöschl, U.
- Published
- 2010
- Full Text
- View/download PDF
39. Soluble mass, hygroscopic growth, and droplet activation of coated soot particles during LACIS Experiment in November (LExNo).
- Author
-
Henning, S., Wex, H., Hennig, T., Kiselev, A., Snider, J. R., Rose, D., Dusek, U., Frank, G. P., Pöschl, U., Kristensson, A., Bilde, M., Tillmann, R., Kiendler-Scharr, A., Mentel, T. F., Walter, S., Schneider, J., Wennrich, C., and Stratmann, F.
- Published
- 2010
- Full Text
- View/download PDF
40. Examination of laboratory-generated coated soot particles: An overview of the LACIS Experiment in November (LExNo) campaign.
- Author
-
Stratmann, F., Bilde, M., Dusek, U., Frank, G. P., Hennig, T., Henning, S., Kiendler-Scharr, A., Kiselev, A., Kristensson, A., Lieberwirth, I., Mentel, T. F., Pöschl, U., Rose, D., Schneider, J., Snider, J. R., Tillmann, R., Walter, S., and Wex, H.
- Published
- 2010
- Full Text
- View/download PDF
41. Humidity influence on gas-particle phase partitioning of α-pinene + O3 secondary organic aerosol.
- Author
-
Prisle, N. L., Engelhart, G. J., Bilde, M., and Donahue, N. M.
- Published
- 2010
- Full Text
- View/download PDF
42. Hygroscopic properties of Amazonian biomass burning and European background HULIS and investigation of their effects on surface tension with two models linking H-TDMA to CCNC data.
- Author
-
Fors, E. O., Rissler, J., Massling, A., Svenningsson, B., Andreae, M. O., Dusek, U., Frank, G. P., Hoffer, A., Bilde, M., Kiss, G., Janitsek, S., Henning, S., Facchini, M. C., Decesari, S., and Swietlicki, E.
- Abstract
HUmic-LIke Substances (HULIS) have been identified as major contributors to the organic carbon in atmospheric aerosol. The term HULIS is used to describe the organic material found in aerosol particles which resembles the humic organic material in river and sea water and in soils. In this study two sets of filter samples from atmospheric aerosols were collected at different sites. One sample was collected at the K-puszta rural site in Hungary, about 80 km SE of Budapest, and a second set of samples was collected at a site in Rondônia, Amazonia, Brazil, during the LBA-SMOCC biomass burning season experiment. HULIS were extracted from the samples, and their hygroscopic properties were studied using a Hygroscopicity Tandem Differential Mobility Analyzer (H-TDMA) at relative humidity (RH) <100%, and a cloud condensation nucleus counter (CCNC) at RH >100%. The H-TDMA measurements were carried out at a dry diameter of 100 nm and for RH ranging from 30 to 98%. At 90% RH the HULIS samples showed diameter growth factors between 1.04 and 1.07, reaching values of 1.4 at 98% RH. The cloud nucleating properties of the two sets of aerosol samples were analyzed using two types of thermal static cloud condensation nucleus counters (CCNC). Two different parameterization models were used to investigate the potential effect of HULIS surface activity, both yielding similar results. For the K-puszta winter HULIS sample, the surface tension at the point of activation was estimated to be lowered by between 34% (47.7 m N/m) and 31% (50.3 m N/m) for dry sizes between 50 and 120 nm in comparison to pure water. A moderate lowering was also observed for the entire water soluble aerosol sample, including both organic and inorganic compounds, where the surface tension was decreased by between 2% (71.2 mN/m) and 13% (63.3 mN/m). [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
43. Surfactants in cloud droplet activation: mixed organic-inorganic particles.
- Author
-
Prisle, N. L., Raatikainen, T., Laaksonen, A., and Bilde, M.
- Abstract
Organic compounds with surfactant properties are commonly found in atmospheric aerosol particles. Surface activity can significantly influence the cloud droplet forming ability of these particles. We have studied the cloud droplet formation by two-component particles comprising one of the organic surfactants sodium octanoate, sodium decanoate, sodium dodecanoate, and sodium dodecyl sulfate, mixed with sodium chloride. Critical supersaturations were measured with a static diffusion cloud condensation nucleus counter (Wyoming CCNC-100B). Results were modeled from Köhler theory applying three different representations of surfactant properties: (1) using concentration-dependent surface tension reduction during droplet growth and explicitly accounting for surfactant surface partitioning in both solute suppression (Raoult effect) and curvature enhancement (Kelvin effect) contributions to the droplet equilibrium water vapor supersaturation, (2) disregarding surfactant partitioning and using a concentration-dependent surface tension for the droplets corresponding to a macroscopic (bulk) aqueous solution of the same overall composition, and (3) disregarding surfactant properties and assuming the constant surface tension of pure water throughout droplet activation. We confirm previous results for single-component organic surfactant particles, that experimental critical supersaturations are greatly underpredicted, if reduced surface tension is applied in Köhler theory while ignoring the effects of surface partitioning in droplets. We further show that assuming the constant surface tension of pure water can also lead to significant underpredictions of experimental critical supersaturations. The full account for surfactant partitioning in activating droplets generally predicts experimental critical supersaturations well. In addition, for mixed particles comprising less than 50% by mass of surfactant, ignoring surfactant properties and simply using the constant surface tension of pure water also provides a good first-order approximation of the observed activation. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
44. Temperature and humidity dependence of secondary organic aerosol yield from the ozonolysis of β-pinene.
- Author
-
Hessberg, C. von, Hessberg, P. von, Pöschl, U., Bilde, M., Nielsen, O. J., and Moortgat, G. K.
- Subjects
ATMOSPHERIC aerosols ,TEMPERATURE ,OZONOLYSIS ,HUMIDITY ,CHEMICAL reactions ,MONOTERPENES ,VOLATILE organic compounds - Abstract
The temperature dependence of secondary organic aerosol (SOA) formation from ozonolysis of β-pinene was studied in a flow reactor at 263 K-303K and 1007 hPa under dry and humid conditions (0% and 26%-68% relative humidity, respectively). The observed SOA yields reached maximum values of 0.18-0.39 at high particle mass concentrations (M[subo]). Under dry conditions, the measurement data showed an overall increase in SOA yield with inverse temperature, but significant oscillatory deviations from the predicted linear increase with inverse temperature (up to 50% at high M[subo]) was observed. Under humid conditions the SOA yield exhibited a linear decrease with inverse temperature. For the atmospherically relevant concentration level of M[subo]=1μgm-3 and temperature range 263 K-293 K, the results from humid experiments in this study indicate that the SOA yield of β-pinene ozonolysis may be well represented by an average value of 0.15 with an uncertainty estimate of ±0.05. When fitting the measurement data with a twoproduct model, both the partitioning coefficients (K[subom],i ) and the stoichiometric yields ( i ) of the low-volatile and semivolatile model species were found to vary with temperature. The results indicate that not only the reaction product vapour pressures but also the relative contributions of different gasphase or multiphase reaction channels are strongly dependent on temperature and the presence of water vapour. In fact, the oscillatory positive temperature dependence observed under dry conditions and the negative temperature dependence observed under humid conditions indicate that the SOA yield is governed much more by the temperature and humidity dependence of the involved chemical reactions than by vapour pressure temperature dependencies. We suggest that the elucidation and modelling of SOA formation need to take into account the effects of temperature and humidity on the pathways and kinetics of the involved chemical reactions as well as on the gas-particle partitioning of the reaction products. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
45. Temperature and humidity dependence of secondary organic aerosol yield from the ozonolysis of ß-pinene.
- Author
-
Stenby, C., Pöschl, U., Von Hessberg, P., Bilde, M., Nielsen, O. J., and Moortgat, G. K.
- Abstract
The temperature dependence of secondary organic aerosol (SOA) formation from ozonolysis of β-pinene was studied in a flow reactor at 263 K-303K and 1007 hPa under dry and humid conditions (0% and 26%-68% relative humidity, respectively). The observed SOA yields were of similar magnitude as predicted by a two-product model based on detailed gas phase chemistry (Jenkin, 2004), reaching maximum values of 0.18-0.39 at high particle mass concentrations (M
0 ). Under dry conditions, however, the measurement data exhibited significant oscillatory deviations from the predicted linear increase with inverse temperature (up to 50% at high M0 ). Under humid conditions the SOA yield exhibited a linear decrease with inverse temperature, which is opposite to modelled temperature dependence and implies that the model substantially overestimates the yield at low temperatures and underestimates it at high temperatures (deviations up to 80% at high M0 ). For the atmospherically relevant concentration level of M0 =10 µg m-3 and temperature range 263 K-293 K, the results from humid experiments in this study indicate that the SOA yield of β-pinene ozonolysis may be well represented by an average value of 0.15 with an uncertainty estimate of ±0.05. When fitting the measurement data with a two-product model, both the partitioning coefficients (Kom,i ) and the stoichiometric yields (αi ) of the low-volatile and semi-volatile model species were found to vary with temperature. The results indicate that not only the reaction product vapour pressures but also the relative contributions of different gas-phase or multiphase reaction channels are strongly dependent on temperature and the presence of water vapour. In fact, the oscillatory positive temperature dependence observed under dry conditions and the negative temperature dependence observed under humid conditions indicate that the SOA yield is governed much more by the temperature and humidity dependence of the involved chemical reactions than by vapour pressure temperature dependencies. We suggest that the elucidation and modelling of SOA formation need to take into account the effects of temperature and humidity on the pathways and kinetics of the involved chemical reactions as well as on the gas-particle partitioning of the reaction products. [ABSTRACT FROM AUTHOR]- Published
- 2007
- Full Text
- View/download PDF
46. Hygroscopic growth and critical supersaturations for mixed aerosol particles of inorganic and organic compounds of atmospheric relevance.
- Author
-
Svenningsson, B., Rissler, J., Swietlicki, E., Mircea, M., Bilde, M., Facchini, M. C., Decesari, S., Fuzzi, S., Zhou, J., Mønster, J., and Rosenørn, T.
- Subjects
SPECTROMETERS ,AIR pollution ,AEROSOLS ,MOISTURE ,WEATHER ,CARBON - Abstract
The organic fraction of atmospheric aerosols contains a multitude of compounds and usually only a small fraction can be identified and quantified. However, a limited number of representative organic compounds can be used to describe the water-soluble organic fraction. In this work, initiated within the EU 5FP project SMOCC, four mixtures containing various amounts of inorganic salts (ammonium sulfate, ammonium nitrate, and sodium chloride) and three model organic compounds (levoglucosan, succinic acid and fulvic acid) were studied. The interaction between water vapor and aerosol particles was studied at different relative humidities: at subsaturation using a hygroscopic tandem differential mobility analyzer (H-TDMA) and at supersaturation using a cloud condensation nuclei spectrometer (CCN spectrometer). Surface tensions as a function of carbon concentrations were measured using a bubble tensiometer. Parameterizations of water activity as a function of molality, based on hygroscopic growth, are given for the pure organic compounds and for the mixtures, indicating van't Hoff factors around 1 for the organics. The Zdanovskii-Stokes-Robinson (ZSR) mixing rule was tested on the hygroscopic growth of the mixtures and it was found to adequately explain the hygroscopic growth for 3 out of 4 mixtures, when the limited solubility of succinic acid is taken into account. One mixture containing sodium chloride was studied and showed a pronounced deviation from the ZSR mixing rule. Critical supersaturations calculated using the parameterizations of water activity and the measured surface tensions were compared with those determined experimentally. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
47. Hygroscopic growth and critical supersaturations for mixed aerosol particles of inorganic and organic compounds of atmospheric relevance.
- Author
-
Svenningsson, B., Rissler, J., Swietlicki, E., Mircea, M., Bilde, M., Facchini, M. C., Decesari, S., Fuzzi, S., Zhou, J., Mønster, J., and Rosenørn, T.
- Abstract
The organic fraction of atmospheric aerosols contains a multitude of compounds and usually only a small fraction can be identified and quantified. However, a limited number of representative organic compounds can be used to describe the water-soluble organic fraction. In this work, initiated within the EU 5FP project SMOCC, four mixtures containing various amounts of inorganic salts (ammonium sulfate, ammonium nitrate, and sodium chloride) and three model organic compounds (levoglucosan, succinic acid and fulvic acid) were studied. The interaction between water vapor and aerosol particles was studied at different relative humidities: at subsaturation using a hygroscopic tandem differential mobility analyzer (H-TDMA) and at supersaturation using a cloud condensation nuclei spectrometer (CCN spectrometer). Surface tensions as a function of carbon concentrations were measured using a bubble tensiometer. Parameterizations of water activity as a function of molality, based on hygroscopic growth, are given for the pure organic compounds and for the mixtures, indicating van't Hoff factors around 1 for the organics. The Zdanovskii-Stokes-Robinson (ZSR) mixing rule was tested on the hygroscopic growth of the mixtures and it was found to adequately explain the hygroscopic growth for 3 out of 4 mixtures, when the limited solubility of succinic acid is taken into account. One mixture containing sodium chloride was studied and showed a pronounced deviation from the ZSR mixing rule. Critical supersaturations calculated using the parameterizations of water activity and the measured surface tensions were compared with those determined experimentally. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
48. Cloud droplet activation and surface tension of mixtures of slightly soluble organics and inorganic salt.
- Author
-
Henning, S., Rosenørn, T., D'Anna, B., Gola, A. A., Svenningsson, B., and Bilde, M.
- Subjects
CLOUDS ,SURFACE tension ,ADIPIC acid ,SUCCINIC acid ,SALT ,SURFACE energy ,SURFACE chemistry ,CAPILLARITY ,LIGHT elements ,SOLUTION (Chemistry) - Abstract
Critical supersaturations for internally mixed particles of adipic acid, succinic acid and sodium chloride were determined experimentally for dry particles sizes in the range 40-130 nm. Surface tensions of aqueous solutions of the dicarboxylic acids and sodium chloride corresponding to concentrations at activation were measured and parameterized as a function of carbon content. The activation of solid particles as well as solution droplets were studied and particle phase was found to be important for the critical supersaturation. Experimental data were modelled using Köhler theory modified to account for limited solubility and surface tension lowering. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
49. Corrigendum to “Evaporation of methyl- and dimethyl-substituted malonic, succinic, glutaric and adipic acid particles at ambient temperatures”: [Journal of Aerosol Science 35 (2004) 1453–1465]
- Author
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Mønster, J., Rosenørn, T., Svenningsson, B., and Bilde, M.
- Published
- 2006
- Full Text
- View/download PDF
50. Evaporation of organic and inorganic/organic particles.
- Author
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Zardini, Alessandro Alessio, Koponen, I., Riipinen, I., Kulmala, M., and Bilde, M.
- Published
- 2009
- Full Text
- View/download PDF
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