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  • 1.
    Weinbruch, Stephan
    et al.
    Tech Univ Darmstadt, Inst Appl Geosci, D-64287 Darmstadt, Germany..
    Wiesemann, David
    Tech Univ Darmstadt, Inst Appl Geosci, D-64287 Darmstadt, Germany..
    Ebert, Martin
    Tech Univ Darmstadt, Inst Appl Geosci, D-64287 Darmstadt, Germany..
    Schuetze, Katharina
    Tech Univ Darmstadt, Inst Appl Geosci, D-64287 Darmstadt, Germany..
    Kallenborn, Roland
    Norwegian Univ Life Sci UMB, Dept Chem Biotechnol & Food Sci IKBM, NO-1432 As, Norway.;Norwegian Inst Air Res NILU, NO-2027 Kjeller, Norway..
    Ström, Johan
    Stockholm Univ, Dept Appl Environm Sci ITM, S-10961 Stockholm, Sweden..
    Chemical composition and sources of aerosol particles at Zeppelin Mountain (Ny Alesund, Svalbard): An electron microscopy study2012In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 49, p. 142-150Article in journal (Refereed)
    Abstract [en]

    Aerosol particles were collected at the Zeppelin Mountain Atmospheric Research Station (474 m asl) near Ny Alesund (Svalbard, Norway) on 27 different days between July 2007 and December 2008. The size, morphology and chemical composition of 57,617 individual particles were studied by high-resolution scanning electron microscopy and energy-dispersive X-ray microanalysis. Based on chemical composition, morphology, mixing state and stability under electron bombardment, the particles were assigned to one of the following groups: sea salt, aged sea salt, Ca sulphates, Na sulphates, carbonates, soot, silicates, fly ashes, secondary aerosol, secondary aerosol plus sodium, secondary aerosol plus soot, mixed particles and others. Sea salt, aged sea salt, silicates and mixed particles (mixtures of sea salt, silicates and Ca sulphates) are the most abundant groups for particles with aerodynamic diameters > 0.5 mu m, secondary aerosol, mixed particles and secondary aerosol with soot inclusions below 0.5 mu m. Silicate fly ashes (major source coal burning) and metal fly ashes (from metallurgical high temperature processes) occur only at very low number concentrations. In contrast to previous work, the fly ash abundance is not correlated with air masses that crossed industrialized regions in Central and Eastern Europe, Scandinavia or Russia. These observations indicate a significant reduction of long-range transport of heavy metals to Svalbard. Soot (external and internally mixed with secondary aerosol) shows a pronounced seasonal pattern with a much lower abundance during summer compared to spring, autumn and winter. The soot abundance is not correlated with the air mass back-trajectories. During summer (July and August), soot was only observed when cruise ships were present in the area around Ny Alesund (Kongsfjorden). Pronounced seasonal patterns were observed for the abundance of the mineral dust component which is generally lower in summer compared to the other seasons. The observed seasonal dependence of anthropogenic primary particles (soot, fly ashes) is in good agreement with the Arctic circulation pattern. (C) 2011 Elsevier Ltd. All rights reserved.

  • 2. Worton, D. R.
    et al.
    Sturges, W. T.
    Reeves, C. E.
    Newland, M. J.
    Penkett, S. A.
    Atlas, E.
    Stroud, V.
    Johnson, K.
    Schmidbauer, N.
    Solberg, S.
    Schwander, J.
    Barnola, J. M.
    Evidence from firn air for recent decreases in non-methane hydrocarbons and a 20th century increase in nitrogen oxides in the northern hemisphere2012In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 54Article in journal (Refereed)
    Abstract [en]

    The atmospheric evolution of eight non-methane hydrocarbons (ethane, acetylene, propane, n-butane, isobutane, n-pentane, isopentane and benzene) and five alkyl nitrates (2-propyl, 2-butyl, 3-methyl-2-butyl and the sum of 2+3-pentyl nitrates) are reconstructed for the latter half of the 20th century based on Arctic firn air measurements. The reconstructed trends of the non-methane hydrocarbons (NMHCs) show increasing concentrations from 1950 to a maximum in 1980 before declining towards the end of last century. These observations provide direct evidence that NMHCs in the northern hemisphere have declined substantially during the period 1980-2001. Benzene concentrations show a smaller increase between 1950 and 1980 than the other NMHCs indicating that additional sources of benzene, other than fossil fuel combustion, were likely important contributors to the benzene budget prior to and during this period. The declining benzene concentrations from 1980 to 2001 would suggest that biomass burning is unlikely to be important in the benzene budget as biomass burning emissions were reportedly increasing over the same period. Methyl and ethyl nitrate show growth patterns in the firn that suggested perturbation by in-situ production from an unidentified mechanism. However, the higher alkyl nitrates show evidence for increasing concentrations from 1950 to maxima in the mid 1990s before decreasing slightly toward the end of the last century. The differing atmospheric evolution of the alkyl nitrates relative to their parent hydrocarbons indicate an increase in their production efficiency per hydrocarbon molecule. Using a steady state analysis of hydrocarbon oxidation and alkyl nitrate production and loss we show that reactive nitrogen oxide (NOx) concentrations in the northern hemisphere have likely increased considerably between 1950 and 2001. (C) 2012 Elsevier Ltd. All rights reserved.

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