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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of atmospheric chemistry 13 (1991), S. 325-342 
    ISSN: 1573-0662
    Keywords: Sulfur dioxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract A new sensitive method for measuring atmospheric concentrations of sulfur dioxide is presented. Samples are obtained using the mist chamber, which collects highly water-soluble gases with high efficiency, and concentrates them in a small volume of water. Particles are removed from the sampled air stream with a teflon filter, before it enters the mist chamber. After collection, the pH of the water is raised above pH 10 using sodium carbonate, then hydrogen peroxide (H2O2) is added to oxidize sulfur that may be present in the sulfur (IV) oxidation state, to sulfate. After a reaction time of at least 16 hours, the sulfate concentration is measured by ion chromatography. From the sulfate concentration, the water volume used in the mist chamber, and the volume of air sampled, the atmospheric concentration of SO2 is computed. The method is not sensitive to other atmospheric sulfur gases such as DMS, SC2, H2S, COS, or MSH. The estimated overall precision of the method is 10%. The detection limit at the present stage of technique development is approximately 20 ppt (parts per trillion, or 10-12 mol · mol-1) for a 45 minute sampling time, with lower concentrations being detectable with lower precision.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of atmospheric chemistry 35 (2000), S. 1-18 
    ISSN: 1573-0662
    Keywords: ozone ; nitrogen oxides ; VOC ; ozone formation ; air pollution ; urban emissions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The ozone forming potential of VOCs and NOx for plumes observed from several cities and a power plant in eastern Germany was investigated. A closed box model with a gas phase photochemical reaction mechanism was employed to simulate several scenarios based upon aircraft observations. In several of the scenarios, the initial concentrations of NOx, VOCs, and SO2, were reduced to study the factors limiting the O3 production. Ozone production was limited by the initial VOC concentrations for all of the simulated plumes. Higher O3 concentrations were produced with reduced initial NOx. In one sample with high SO2 mixing ratios (〉100 ppb), SO2 was also identified as a significant contributor to the production of O3.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 49 (1990), S. 35-50 
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract At three locations in NE-Bavaria (Central Europe), aerosol particles were collected in five size fractions with a cascade impactor. The water soluble part of each fraction was analyzed for major ions and strong, weak and neutralizing acidities. For reliable determination of these categories of acidity, a comparison between different methods was initially performed. Further study revealed a distinct difference in amount and character of the acidity between fine (Dp 〈 1.35 μm) and coarse (Dp 〉 4.05 μm) particles. Fine particles always reacted acidic and their acidity was mainly due to strong acids. Concentrations were highest in polluted urban air, where additional weak organic acids were present in fine particles. The in situ pH's were calculated as pH 1...2 for these particles at all sampling sites. Coarse particles were only slightly acidic, with a mean in situ pH 5.5...6.5. Their acidity was mainly caused by weak acids, especially hydroxilized metal ions dominated by Al.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Meteorology and atmospheric physics 34 (1984), S. 75-81 
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Description / Table of Contents: Summary Samples of fog and rain water have been weekly collected near Bad Steben/Frankenwald Mountains (N-Bavaria) and evaporated while the corresponding pH-changes have been detected. Rain waters with initial pH’s about 4.3 showed theoretical value depressions corresponding to the decreased sample volumes. The detected slopes of fog water pH’s deviated slightly when below pH = 4 while still dropping until pH’s below 2. In one rain water sample the initial pH of 5.7 dropped only for .2 units which fits well to the assumption of degassing action cif CO2 as the predominant gaseous acid component in the solution. Considering forest dying as caused by impact of strong acid deposition, the results suggest that - pH’s on leaf surfaces may be much lower than in the original rain or fog waters - coniferous trees should be more endangered by decreased pH’s than deciduous trees because they usually have larger wetting surfaces and longer wetting times - periods of dry weather after rainfall should enhance the pH-dependent damages.
    Notes: Zusammenfassung Nebel- und Regenwasserproben aus dem Frankenwald nahe Bad Steben (N-Bayern) wurden wöchentlich gesammelt und milde eingedampft. Dabei wurde die Änderung des pH-Wertes gemessen. Regenwasserproben mit anfänglichen pH-Werten um 4,3 zeigten pH-Wert-Erniedrigungen, die aufgrund entsprechender theoretischer Gberlegungen bezüglich des Einflusses von Säurestärken und Volumeneinengung zu erwarten waren. Geringfügige Abweichungen hiervon wurden im Nebelwasser bei pH 〈 4 gefunden. Eine Regenwasserprobe mit anfänglich pH = 5,7 änderte ihren Wert nur um −0,2 Einheiten, was eine Säureanhydridentgasung (CO2) vermuten läßt. Im Hinblick auf säurebedingtes Waldsterben kann dabei folgendes festgestellt werden: - pH-Werte am Einwirkungsort auf der Pflanze können wesentlich niedriger sein als im Regen- bzw. im Nebelwasser gemessen; - Nadelbäume sollten gegenüber Laubbäumen in höherem Maße pH-Erniedrigungen ausgesetzt sein, da die Benetzungsfläche und die Benetzungsdicke ganzjährig größer sind; - Trockenphasen im Anschluß an Niederschlagsereignisse sollten die Einwirkungszeit erniedrigter pH-Werte auf die Pflanze verlängern und damit die direkte Säureschädigung noch verstärken.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-4483
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Description / Table of Contents: Zusammenfassung An zwei entlegenen Meßstellen der Südinsel Neuseelands und an zwei Meßstellen im Fichtelgebirge haben wir die Ionen im Regen und Nebel gemessen. Die Luftverschmutzung im Fichtelgebirge ist gekennzeichnet durch hohe Konzentrationen von H3O+, NO 3 − , SO 4 2− und NH 4 + . Die Ionenkonzentrationen im neuseeländischen Niederschlagswasser waren durchwegs sehr gering mit Ausnahme von Na+, Cl− und Mg2+, die aus Seesalzen stammen und nur in einer küstennahen Meßstelle bei günstigen Wetterlagen bestimmt werden konnten. Große Unterschiede bestehen in der Azidität der Hydrometeore. Während im Fichtelgebirge starke Mineralsäuren niedrige pH-Werte (pH ≈ 4.2) bewirken, wird die Azidität des Regens und des Nebels an den neuseeländischen Meßstellen durch gelöstes CO2 kontrolliert (pH ≈ 5.6). Im Fichtelgebirge ist die Azidität im Nebel erheblich höher als im Regen. Im Gegensatz dazu konnten wir keinen Unterschied in der Azidität zwischen Nebel und Regen in Neuseeland beobachten, was wir mit dem marinen Einfluß und dem Fehlen starker Mineralsäuren erklären. Unterschiedliche Trajektorien der atmosphärischen Strömung in Neuseeland unterscheiden sich zugleich in ihren Ionenkonzentrationen im Regen.
    Notes: Summary We measured ionic compounds in rain and fog at two remote sites in the South Island of New Zealand and at two sites in the Fichtelgebirge, F. R. of Germany. In the Fichtelgebirge high concentrations of H3O+, NO 3 − , SO 4 2− and NH 4 + indicate an anthropogenic impact, whereas in New Zealand concentrations were generally very low except for seasalt derived ions such as Na+, Cl− and Mg2+ at one site near the coast which receives precipitation from maritime sources. Remarkable differences occur in the acidity of hydrometeors in New Zealand and the Fichtelgebirge. The low pH values of the Fichtelgebirge (pH ≈ 4.2) are due to an excess of strong mineral acids, whereas the acidity of rain and fog in New Zealand is controlled by dissolved CO2 (pH ≈ 5.6). In the Fichtelgebirge, acidity in fog is much higher than in rain, whereas no difference could be observed in New Zealand due to marine influences and the lack of strong mineral acids. Rain of different trajectories of air flow in New Zealand is accompanied by a wide range of ionic concentrations.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 23 (1940), S. 25-27 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 23 (1940), S. 1441-1444 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 23 (1940), S. 1444-1445 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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