<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" dtd-version="3.0" xml:lang="en">
<front>
<journal-meta>
<journal-id journal-id-type="publisher">ACPD</journal-id>
<journal-title-group>
<journal-title>Atmospheric Chemistry and Physics Discussions</journal-title>
<abbrev-journal-title abbrev-type="publisher">ACPD</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">1680-7375</issn>
<publisher><publisher-name>Copernicus GmbH</publisher-name>
<publisher-loc>GÃ¶ttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/acpd-11-23959-2011</article-id>
<title-group>
<article-title>Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;, O&lt;sub&gt;3&lt;/sub&gt; and iron catalysis</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Harris</surname>
<given-names>E.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Sinha</surname>
<given-names>B.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Hoppe</surname>
<given-names>P.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Crowley</surname>
<given-names>J. N.</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Ono</surname>
<given-names>S.</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Foley</surname>
<given-names>S.</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Abteilung Partikelchemie, Max-Planck-Institut fÃ¼r Chemie, Becherweg 27, 55128 Mainz, Germany</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Abteilung Luftchemie, Max-Planck-Institut fÃ¼r Chemie, Becherweg 27, 55128 Mainz, Germany</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Earth System Science Research Centre, Institute for Geosciences, University of Mainz, Becherweg 21, 55128 Mainz, Germany</addr-line>
</aff>
<pub-date pub-type="epub">
<day>25</day>
<month>08</month>
<year>2011</year>
</pub-date>
<volume>11</volume>
<issue>8</issue>
<fpage>23959</fpage>
<lpage>24002</lpage>
<permissions>
<license xlink:type="simple">
<license-p>This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.</license-p>
</license>
</permissions>
<self-uri xlink:href="http://www.atmos-chem-phys-discuss.net/11/23959/2011/acpd-11-23959-2011.html">This article is available from http://www.atmos-chem-phys-discuss.net/11/23959/2011/acpd-11-23959-2011.html</self-uri>
<self-uri xlink:href="http://www.atmos-chem-phys-discuss.net/11/23959/2011/acpd-11-23959-2011.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/11/23959/2011/acpd-11-23959-2011.pdf</self-uri>
<abstract>
<p>The oxidation of SO&lt;sub&gt;2&lt;/sub&gt; to sulfate is a key reaction in determining the role
of sulfate in the environment through its effect on aerosol size distribution
and composition. Sulfur isotope analysis has been used to investigate sources
and chemistry of sulfur dioxide and sulfate in the atmosphere, however
interpretation of measured sulfur isotope ratios is challenging due to a lack
of reliable information on the isotopic fractionation involved in major
transformation pathways. This paper presents measurements of the
fractionation factors for the major atmospheric oxidation reactions for
SO&lt;sub&gt;2&lt;/sub&gt;: Gas-phase oxidation by OH radicals, and aqueous oxidation by
H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;, O&lt;sub&gt;3&lt;/sub&gt; and a radical chain reaction initiated by iron. The
measured fractionation factor for &lt;sup&gt;34&lt;/sup&gt;S/&lt;sup&gt;32&lt;/sup&gt;S during the gas-phase
reaction is &amp;alpha;&lt;sub&gt;OH&lt;/sub&gt; = (1.0089&amp;plusmn;0.0007) &amp;minus;
((4&amp;plusmn;5)&amp;times;10&lt;sup&gt;&amp;minus;5&lt;/sup&gt;) &lt;i&gt;T&lt;/i&gt;(Â°C). The measured fractionation
factor for &lt;sup&gt;34&lt;/sup&gt;S/&lt;sup&gt;32&lt;/sup&gt;S during aqueous oxidation by H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; or O&lt;sub&gt;3&lt;/sub&gt;
is &amp;alpha;&lt;sub&gt;aq&lt;/sub&gt;=(1.0167&amp;plusmn;0.0019) &amp;minus; ((8.7&amp;plusmn;3.5)
&amp;times;10&lt;sup&gt;&amp;minus;5&lt;/sup&gt;) &lt;i&gt;T&lt;/i&gt;(Â°C). The observed fractionation during
oxidation by H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;3&lt;/sub&gt; appeared to be controlled primarily by
protonation and acid-base equilbria of S(IV) in solution, and there was no
significant difference between the fractionation produced by the two oxidants
within the experimental error. The isotopic fractionation factor from a
radical chain reaction in solution catalysed by iron is &amp;alpha;&lt;suB&gt;Fe&lt;/sub&gt; =
(0.989&amp;plusmn;0.0043) at 19 Â°C for &lt;sup&gt;34&lt;/sup&gt;S/&lt;sup&gt;32&lt;/sup&gt;S. Fractionation
was mass-dependent with regards to &lt;sup&gt;33&lt;/sup&gt;S for all the reactions
investigated. The radical chain reaction mechanism was the only measured
reaction that had a faster rate for the light isotopes, and will be
particularly useful to determine the importance of the transition-metal
catalysed oxidation pathway.</p>
</abstract>
<counts><page-count count="44"/></counts>
</article-meta>
</front>
<body/>
<back>
<ref-list>
<title>References</title>
<ref id="ref1">
<label>1</label><mixed-citation publication-type="other" xlink:type="simple"> Alexander, B., Savarino, J., Barkov, N I., Delmas, R J., and Thiemens, M H.: Climate driven changes in the oxidation pathways of atmospheric sulfur, Geophys. Res. Lett., 29, 1685, http://dx.doi.org/10.1029/2002GL014879doi:10.1029/2002GL014879, 2002. </mixed-citation>
</ref>
<ref id="ref2">
<label>2</label><mixed-citation publication-type="other" xlink:type="simple"> Alexander, B., Thiemens, M H., Farquhar, J., Kaufman, A J., Savarino, J., and Delmas, R J.: East Antarctic ice core sulfur isotope measurements over a complete glacial-interglacial cycle, J. Geophys. Res.-Atmos., 108, 4786, http://dx.doi.org/10.1029/2003JD003513doi:10.1029/2003JD003513, 2003. </mixed-citation>
</ref>
<ref id="ref3">
<label>3</label><mixed-citation publication-type="other" xlink:type="simple"> Atkinson, R., Baulch, D. L., Cox, R. A., Crowley, J. N., Hampson, R. F., Hynes, R. G., Jenkin, M. E., Rossi, M. J., and Troe, J.: Evaluated kinetic and photochemical data for atmospheric chemistry: Volume I - gas phase reactions of O&lt;sub&gt;x&lt;/sub&gt;, HO&lt;sub&gt;x&lt;/sub&gt;, NO&lt;sub&gt;x&lt;/sub&gt; and SO&lt;sub&gt;x&lt;/sub&gt; species, Atmos. Chem. Phys., 4, 1461â€“1738, http://dx.doi.org/10.5194/acp-4-1461-2004doi:10.5194/acp-4-1461-2004, 2004. </mixed-citation>
</ref>
<ref id="ref4">
<label>4</label><mixed-citation publication-type="other" xlink:type="simple"> Baroni, M., Thiemens, M H., Delmas, R J., and Savarino, J.: Mass-independent sulfur isotopic compositions in stratospheric volcanic eruptions, Science, 315, 84â€“87, 2007. </mixed-citation>
</ref>
<ref id="ref5">
<label>5</label><mixed-citation publication-type="other" xlink:type="simple"> Baroni, M., Savarino, J., Cole-Dai, J H., Rai, V K., and Thiemens, M H.: Anomalous sulfur isotope compositions of volcanic sulfate over the last millennium in Antarctic ice cores, J. Geophys. Res.-Atmos., 113, D20112, http://dx.doi.org/10.1029/2008JD010185doi:10.1029/2008JD010185, 2008. </mixed-citation>
</ref>
<ref id="ref6">
<label>6</label><mixed-citation publication-type="other" xlink:type="simple"> Benson, D R., Young, L H., Kameel, F R., and Lee, S H.: Laboratory-measured nucleation rates of sulfuric acid and water binary homogeneous nucleation from the SO2 + OH reaction, Geophys. Res. Lett., 35, L11801, http://dx.doi.org/10.1029/2008GL033387doi:10.1029/2008GL033387, 2008. </mixed-citation>
</ref>
<ref id="ref7">
<label>7</label><mixed-citation publication-type="other" xlink:type="simple"> Berresheim, H., Elste, T., Tremmel, H G., Allen, A G., Hansson, H C., Rosman, K., Dal~Maso, M., Makela, J M., Kulmala, M., and O&apos;Dowd, C D.: Gas-aerosol relationships of H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;, MSA, and OH: Observations in the coastal marine boundary layer at Mace Head, Ireland, J. Geophys. Res.-Atmos., 107, 8100, http://dx.doi.org/10.1029/2000JD000229doi:10.1029/2000JD000229, 2002. </mixed-citation>
</ref>
<ref id="ref8">
<label>8</label><mixed-citation publication-type="other" xlink:type="simple"> Bevington, P. and Robinson, D.: Data Reduction and Error Analysis for the Physical Sciences, Mc-Graw Hill, 23â€“28, 1992. </mixed-citation>
</ref>
<ref id="ref9">
<label>9</label><mixed-citation publication-type="other" xlink:type="simple"> Botha, C F., Hahn, J., Pienaar, J J., and Vaneldik, R.: Kinetics and mechanism of the oxidation of sulfur(IV) by ozone in aqueous solutions, Atmos. Environ., 28, 3207â€“3212, 1994. </mixed-citation>
</ref>
<ref id="ref10">
<label>10</label><mixed-citation publication-type="other" xlink:type="simple"> Bower, K N. and Choularton, T W.: Cloud processing of the Cloud Condensation Nucleus spectrum and its climatological consequences, Q. J. Roy. Meteorol. Soc., 119, 655â€“679, 1993. </mixed-citation>
</ref>
<ref id="ref11">
<label>11</label><mixed-citation publication-type="other" xlink:type="simple"> Cantrell, C A., Zimmer, A., and Tyndall, G S.: Absorption cross sections for water vapor from 183 to 193 nm, Geophys. Res. Lett., 24, 2195â€“2198, 1997. </mixed-citation>
</ref>
<ref id="ref12">
<label>12</label><mixed-citation publication-type="other" xlink:type="simple"> Caron, F., Tessier, A., Kramer, J R., Schwarcz, H P., and Rees, C E.: Sulfur and oxygen isotopes of sulfate in precipitation and lakewater, Quebec, Canada, Appl. Geochem., 1, 601â€“606, 1986. </mixed-citation>
</ref>
<ref id="ref13">
<label>13</label><mixed-citation publication-type="other" xlink:type="simple"> Castleman, A W., Munkelwitz, H R., and Manowitz, B.: Isotopic Studies of Sulfur Component of Stratospheric Aerosol Layer, Tellus, 26, 222â€“234, 1974. </mixed-citation>
</ref>
<ref id="ref14">
<label>14</label><mixed-citation publication-type="other" xlink:type="simple"> Chin, M., Jacob, D J., Gardner, G M., ForemanFowler, M S., Spiro, P A., and Savoie, D L.: A global three-dimensional model of tropospheric sulfate, J. Geophys. Res.-Atmos., 101, 18667â€“18690, 1996. </mixed-citation>
</ref>
<ref id="ref15">
<label>15</label><mixed-citation publication-type="other" xlink:type="simple"> Chmielewski, A G., Derda, M., Wierzchnicki, R., and Mikolajczuk, A.: Sulfur isotope effects for the SO&lt;sub&gt;2&lt;/sub&gt;(g)-SO&lt;sub&gt;2&lt;/sub&gt;(aq) system, Nukleonika, 47, S69â€“S70, 2002. </mixed-citation>
</ref>
<ref id="ref16">
<label>16</label><mixed-citation publication-type="other" xlink:type="simple"> Ding, T., Valkiers, S., Kipphardt, H., De~Bievre, P., Taylor, P. D P., Gonfiantini, R., and Krouse, R.: Calibrated sulfur isotope abundance ratios of three IAEA sulfur isotope reference materials and V-CDT with a reassessment of the atomic weight of sulfur, Geochimi. Cosmochim. Acta, 65, 2433â€“2437, 2001. </mixed-citation>
</ref>
<ref id="ref17">
<label>17</label><mixed-citation publication-type="other" xlink:type="simple"> Egiazarov, A C., Kaviladze, M., Kerner, M N., Oziashvili, E L., Ebralidze, A., and Esakiya, A D.: Separation of Sulfur Isotopes by Chemical Exchange, Isotopenpraxis: Isotopes in Environmental and Health Studies, 7, 379â€“383, 1971. </mixed-citation>
</ref>
<ref id="ref18">
<label>18</label><mixed-citation publication-type="other" xlink:type="simple"> Eriksen, T E.: Sulfur Isotope Effects 1. Isotopic Exchange Coefficient for Sulfur Isotopes 34S-32S in System SO2(g)-HSO3(aq) at 25, 35, and 45 Degrees C, Acta Chemica Scandinavica, 26, 573, 1972a. </mixed-citation>
</ref>
<ref id="ref19">
<label>19</label><mixed-citation publication-type="other" xlink:type="simple"> Eriksen, T E.: Sulfur Isotope Effects 2. Isotopic Exchange Coefficients for Sulfur Isotopes 34S-32S in System SO2(g)-Aqueous Solutions of SO&lt;sub&gt;2&lt;/sub&gt;, Acta Chem. Scand., 26, 581, 1972b. </mixed-citation>
</ref>
<ref id="ref20">
<label>20</label><mixed-citation publication-type="other" xlink:type="simple"> Eriksen, T E.: Sulfur Isotope Effects 3. Enrichment of 34S by Chemical Exchange between SO2(g) and Aqueous Solutions of SO&lt;sub&gt;2&lt;/sub&gt;, Acta Chem. Scand., 26, 975, 1972c. </mixed-citation>
</ref>
<ref id="ref21">
<label>21</label><mixed-citation publication-type="other" xlink:type="simple"> Eriksen, T E.: Sulfur Isotope Effects 4. Sulfur Isotope Effects in Anion-Exchange Systems, Acta Chemica Scandinavica, 26, 980, 1972d. </mixed-citation>
</ref>
<ref id="ref22">
<label>22</label><mixed-citation publication-type="other" xlink:type="simple"> Farquhar, J., Savarino, J., Airieau, S., and Thiemens, M H.: Observation of wavelength-sensitive mass-independent sulfur isotope effects during SO2 photolysis: Implications for the early atmosphere, J. Geophys. Res.-Plan., 106, 32829â€“32839, 2001. </mixed-citation>
</ref>
<ref id="ref23">
<label>23</label><mixed-citation publication-type="other" xlink:type="simple"> Goldstein, D. E., N., Echlin, P., Joy, D., Fiori, C., and Lifshin, E.: Scanning Electron Microscopy and X-ray Microanalysis, Plenum Press, New York, USA, 1981. </mixed-citation>
</ref>
<ref id="ref24">
<label>24</label><mixed-citation publication-type="other" xlink:type="simple"> Groener, E. and Hoppe, P.: Automated ion imaging with the NanoSIMS ion microprobe, Appl. Surf. Sci., 252, 7148â€“7151, http://dx.doi.org/10.1016/j.apsusc.2006.02.280doi:10.1016/j.apsusc.2006.02.280, 2006. </mixed-citation>
</ref>
<ref id="ref25">
<label>25</label><mixed-citation publication-type="other" xlink:type="simple"> Guo, Z B., Li, Z Q., Farquhar, J., Kaufman, A J., Wu, N P., Li, C., Dickerson, R R., and Wang, P C.: Identification of sources and formation processes of atmospheric sulfate by sulfur isotope and scanning electron microscope measurements, J. Geophys. Res.-Atmos., 115, D00K07, http://dx.doi.org/10.1029/2009JD012893doi:10.1029/2009JD012893, 2010. </mixed-citation>
</ref>
<ref id="ref26">
<label>26</label><mixed-citation publication-type="other" xlink:type="simple"> Hanson, D R. and Eisele, F.: Diffusion of H2SO4 in humidified nitrogen: Hydrated H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;, J. Phys. Chem. A, 104, 1715â€“1719, 2000. </mixed-citation>
</ref>
<ref id="ref27">
<label>27</label><mixed-citation publication-type="other" xlink:type="simple"> Herrmann, H., Ervens, B., Jacobi, H W., Wolke, R., Nowacki, P., and Zellner, R.: CAPRAM2.3: A chemical aqueous phase radical mechanism for tropospheric chemistry, J. Atmos. Chem., 36, 231â€“284, 2000. </mixed-citation>
</ref>
<ref id="ref28">
<label>28</label><mixed-citation publication-type="other" xlink:type="simple"> Hoppe, P.: NanoSIMS: A new tool in cosmochemistry, Appl. Surf. Sci., 252, 7102â€“7106, 2006. </mixed-citation>
</ref>
<ref id="ref29">
<label>29</label><mixed-citation publication-type="other" xlink:type="simple"> Huygen, C.: The sampling of sulfur dioxide in air with impregnated filter paper, Anal. Chim. Acta, 28, 349â€“360, 1963. </mixed-citation>
</ref>
<ref id="ref30">
<label>30</label><mixed-citation publication-type="other" xlink:type="simple"> IPCC: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007, Cambridge University Press, http://www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html, 2007. </mixed-citation>
</ref>
<ref id="ref31">
<label>31</label><mixed-citation publication-type="other" xlink:type="simple"> Krouse, H R. and Grinenko, V A.: Stable isotopes : natural and anthropogenic sulphur in the environment, vol 43, Wiley, Chichester, UK, 1991. </mixed-citation>
</ref>
<ref id="ref32">
<label>32</label><mixed-citation publication-type="other" xlink:type="simple"> Kulmala, M., Vehkamaki, H., Petaja, T., Maso, M D., Lauri, A., Kerminen, V M., Birmili, W., and McMurry, P H.: Formation and growth rates of ultrafine atmospheric particles: a review of observations, J. Aerosol Sci., 35, 143â€“176, 2004. </mixed-citation>
</ref>
<ref id="ref33">
<label>33</label><mixed-citation publication-type="other" xlink:type="simple"> Lai, A C.: Investigation of Electrostatic Forces on Particle Deposition in a Test Chamber, Indoor Built Environ., 15, 179â€“186, 2006. </mixed-citation>
</ref>
<ref id="ref34">
<label>34</label><mixed-citation publication-type="other" xlink:type="simple"> Leung, F Y., Colussi, A J., and Hoffmann, M R.: Sulfur isotopic fractionation in the gas-phase oxidation of sulfur dioxide initiated by hydroxyl radicals, J. Phys. Chem. A, 105, 8073â€“8076, 2001. </mixed-citation>
</ref>
<ref id="ref35">
<label>35</label><mixed-citation publication-type="other" xlink:type="simple"> Luz, B. and Barkan, E.: The isotopic ratios O-17/O-16 and O-18/O-16 in molecular oxygen and their significance in biogeochemistry, Geochim. Cosmochim. Acta, 69, 1099â€“1110, 2005. </mixed-citation>
</ref>
<ref id="ref36">
<label>36</label><mixed-citation publication-type="other" xlink:type="simple"> Lyons, J R.: Atmospherically-derived mass-independent sulfur isotope signatures, and incorporation into sediments, Chem. Geol., 267, 164â€“174, 2009. </mixed-citation>
</ref>
<ref id="ref37">
<label>37</label><mixed-citation publication-type="other" xlink:type="simple"> Mariotti, A., Germon, J C., Hubert, P., Kaiser, P., Letolle, R., Tardieux, A., and Tardieux, P.: Experimental-determination of Nitrogen Kinetic Isotope Fractionation - Some Principles â€“ Illustration For the Denitrification and Nitrification Processes, Plant Soil, 62, 413â€“430, 1981. </mixed-citation>
</ref>
<ref id="ref38">
<label>38</label><mixed-citation publication-type="other" xlink:type="simple"> Mertes, S., Lehmann, K., Nowak, A., Massling, A., and Wiedensohler, A.: Link between aerosol hygroscopic growth and droplet activation observed for hill-capped clouds at connected flow conditions during FEBUKO, Atmos. Environ., 39, 4247â€“4256, 2005. </mixed-citation>
</ref>
<ref id="ref39">
<label>39</label><mixed-citation publication-type="other" xlink:type="simple"> Moore, J., Stanitski, C., and Jurs, P.: Chemistry: The Molecular Science, Brooks/Cole â€“ Thomson Learning, USA, 2005. </mixed-citation>
</ref>
<ref id="ref40">
<label>40</label><mixed-citation publication-type="other" xlink:type="simple"> Mukai, H., Tanaka, A., Fujii, T., Zeng, Y Q., Hong, Y T., Tang, J., Guo, S., Xue, H S., Sun, Z L., Zhou, J T., Xue, D M., Zhao, J., Zhai, G H., Gu, J L., and Zhai, P Y.: Regional characteristics of sulfur and lead isotope ratios in the atmosphere at several Chinese urban sites, Environ. Sci. Technol., 35, 1064â€“1071, 2001. </mixed-citation>
</ref>
<ref id="ref41">
<label>41</label><mixed-citation publication-type="other" xlink:type="simple"> Norman, A L., Anlauf, K., Hayden, K., Thompson, B., Brook, J R., Li, S M., and Bottenheim, J.: Aerosol sulphate and its oxidation on the Pacific NW coast: S and O isotopes in PM$_2.5$, Atmos. Environ., 40, 2676â€“2689, 2006. </mixed-citation>
</ref>
<ref id="ref42">
<label>42</label><mixed-citation publication-type="other" xlink:type="simple"> Novak, M., Bottrell, S H., and Prechova, E.: Sulfur isotope inventories of atmospheric deposition, spruce forest floor and living Sphagnum along a NW-SE transect across Europe, Biogeochemistry, 53, 23â€“50, 2001a. </mixed-citation>
</ref>
<ref id="ref43">
<label>43</label><mixed-citation publication-type="other" xlink:type="simple"> Novak, M., Jackova, I., and Prechova, E.: Temporal Trends in the Isotope Signature of Air-Borne Sulfur in Central Europe, Environ. Sci. Technol., 35, 255â€“260, 2001b. </mixed-citation>
</ref>
<ref id="ref44">
<label>44</label><mixed-citation publication-type="other" xlink:type="simple"> Nriagu, J O., Rees, C., Mekhtiyeva, V., Lein, A., Fritz, P., Drimmie, R., Pankina, R., Robinson, B., and Krouse, H R.: Stable Isotopes: Natural and Anthropogenic Sulphur in the Environment, chap 6., John Wiley and Sons, 177â€“266, 1991. </mixed-citation>
</ref>
<ref id="ref45">
<label>45</label><mixed-citation publication-type="other" xlink:type="simple"> Ohizumi, T., Fukuzaki, N., and Kusakabe, M.: Sulfur isotopic view on the sources of sulfur in atmospheric fallout along the coast of the Sea of Japan, Atmos. Environ., 31, 1339â€“1348, 1997. </mixed-citation>
</ref>
<ref id="ref46">
<label>46</label><mixed-citation publication-type="other" xlink:type="simple"> Ono, S., Wing, B., Johnston, D., Farquhar, J., and Rumble, D.: Mass-dependent fractionation of quadruple stable sulfur isotope system as a new tracer of sulfur biogeochemical cycles, Geochim. Cosmochim. Acta, 70, 2238â€“2252, 2006a. </mixed-citation>
</ref>
<ref id="ref47">
<label>47</label><mixed-citation publication-type="other" xlink:type="simple"> Ono, S., Wing, B., Rumble, D., and Farquhar, J.: High precision analysis of all four stable isotopes of sulfur (S-32, S-33, S-34 and S-36) at nanomole levels using a laser fluorination isotope-ratio-monitoring gas chromatography-mass spectrometry, Chem. Geol., 225, 30â€“39, 2006b. </mixed-citation>
</ref>
<ref id="ref48">
<label>48</label><mixed-citation publication-type="other" xlink:type="simple"> Patris, N., Delmas, R J., and Jouzel, J.: Isotopic signatures of sulfur in shallow Antarctic ice cores, J. Geophys. Res.-Atmos., 105, 7071â€“7078, 2000. </mixed-citation>
</ref>
<ref id="ref49">
<label>49</label><mixed-citation publication-type="other" xlink:type="simple"> Rees, C. and Holt, B.: Stable Isotopes: Natural and Anthropogenic Sulphur in the Environment, chap 3., John Wiley and Sons, 43â€“64, 1991. </mixed-citation>
</ref>
<ref id="ref50">
<label>50</label><mixed-citation publication-type="other" xlink:type="simple"> Rees, C E., Jenkins, W J., and Monster, J.: Sulfur Isotopic Composition of Ocean Water Sulfate, Geochim. Cosmochim. Acta, 42, 377â€“381, 1978. </mixed-citation>
</ref>
<ref id="ref51">
<label>51</label><mixed-citation publication-type="other" xlink:type="simple"> Saltzman, E S., Brass, G., and Price, D.: The mechanism of sulfate aerosol formation: Chemical and sulfur isotopic evidence, Geophys. Res. Lett., 10, 513â€“516, 1983. </mixed-citation>
</ref>
<ref id="ref52">
<label>52</label><mixed-citation publication-type="other" xlink:type="simple"> Savarino, J., Lee, C. C W., and Thiemens, M H.: Laboratory oxygen isotopic study of sulfur (IV) oxidation: Origin of the mass-independent oxygen isotopic anomaly in atmospheric sulfates and sulfate mineral deposits on Earth, J. Geophys. Res.-Atmos., 105, 29079â€“29088, 2000. </mixed-citation>
</ref>
<ref id="ref53">
<label>53</label><mixed-citation publication-type="other" xlink:type="simple"> Seinfeld, J H. and Pandis, S N.: Atmospheric Chemistry and Physics, Wiley &amp; Sons, New York, USA, 1203, 1998. </mixed-citation>
</ref>
<ref id="ref54">
<label>54</label><mixed-citation publication-type="other" xlink:type="simple"> Sinha, B. W., Hoppe, P., Huth, J., Foley, S., and Andreae, M. O.: Sulfur isotope analyses of individual aerosol particles in the urban aerosol at a central European site (Mainz, Germany), Atmos. Chem. Phys., 8, 7217â€“7238, http://dx.doi.org/10.5194/acp-8-7217-2008doi:10.5194/acp-8-7217-2008, 2008a. </mixed-citation>
</ref>
<ref id="ref55">
<label>55</label><mixed-citation publication-type="other" xlink:type="simple"> Sinha, V., Williams, J., Crowley, J. N., and Lelieveld, J.: The Comparative Reactivity Method â€“ a new tool to measure total OH Reactivity in ambient air, Atmos. Chem. Phys., 8, 2213â€“2227, http://dx.doi.org/10.5194/acp-8-2213-2008doi:10.5194/acp-8-2213-2008, 2008b. </mixed-citation>
</ref>
<ref id="ref56">
<label>56</label><mixed-citation publication-type="other" xlink:type="simple"> Sinha, V., Custer, T G., Kluepfel, T., and Williams, J.: The effect of relative humidity on the detection of pyrrole by PTR-MS for OH reactivity measurements, Int. J. Mass Spectrom., 282, 108â€“111, 2009. </mixed-citation>
</ref>
<ref id="ref57">
<label>57</label><mixed-citation publication-type="other" xlink:type="simple"> Slodzian, G., Chaintreau, M., Dennebouy, R., and Rousse, A.: Precise in situ measurements of isotopic abundances with pulse counting of sputtered ions, Europ. Phys. J.-Appl. Phys., 14, 199â€“231, 2001. </mixed-citation>
</ref>
<ref id="ref58">
<label>58</label><mixed-citation publication-type="other" xlink:type="simple"> Slodzian, G., Hillion, F., Stadermann, F J., and Zinner, E.: QSA influences on isotopic ratio measurements, Appl. Surf. Sci., 231-2, 874â€“877, 2004. </mixed-citation>
</ref>
<ref id="ref59">
<label>59</label><mixed-citation publication-type="other" xlink:type="simple"> Sofen, E. D., Alexander, B., and Kunasek, S. A.: The impact of anthropogenic emissions on atmospheric sulfate production pathways, oxidants, and ice core $\Delta^17$O(SO$_4^2–$), Atmos. Chem. Phys., 11, 3565-3578, http://dx.doi.org/10.5194/acp-11-3565-2011doi:10.5194/acp-11-3565-2011, 2011. </mixed-citation>
</ref>
<ref id="ref60">
<label>60</label><mixed-citation publication-type="other" xlink:type="simple"> Stoyan, D.: Stochastik fuer Ingenieure und Naturwissenschaftler, Wiley-VCH, 1998. </mixed-citation>
</ref>
<ref id="ref61">
<label>61</label><mixed-citation publication-type="other" xlink:type="simple"> Tanaka, N., Rye, D M., Xiao, Y., and Lasaga, A C.: Use of Stable Sulfur Isotope Systematics for Evaluating Oxidation Reaction Pathways and in-Cloud Scavenging of Sulfur-Dioxide in the Atmosphere, Geophys. Res. Lett., 21, 1519â€“1522, 1994. </mixed-citation>
</ref>
<ref id="ref62">
<label>62</label><mixed-citation publication-type="other" xlink:type="simple"> US-EPA: Method 6 â€“ Determination of Sulfur Dioxide Emissions from Stationary Sources, http://www.epa.gov/ttn/emc/, 2010. </mixed-citation>
</ref>
<ref id="ref63">
<label>63</label><mixed-citation publication-type="other" xlink:type="simple"> Winterholler, B.: Sulfur Isotope Analysis of Aerosol Particles by NanoSIMS, Ph.D. thesis, Johannes Gutenberg-Universitaet, Mainz, Germany, 2007. </mixed-citation>
</ref>
<ref id="ref64">
<label>64</label><mixed-citation publication-type="other" xlink:type="simple"> Winterholler, B., Hoppe, P., Andreae, M O., and Foley, S.: Measurement of sulfur isotope ratios in micrometer-sized samples by NanoSIMS, Appl. Surf. Sci., 252, 7128â€“7131, 2006. </mixed-citation>
</ref>
<ref id="ref65">
<label>65</label><mixed-citation publication-type="other" xlink:type="simple"> Winterholler, B., Hoppe, P., Foley, S., and Andreae, M O.: Sulfur isotope ratio measurements of individual sulfate particles by NanoSIMS, Int. J. Mass Spectrom., 272, 63â€“77, 2008. </mixed-citation>
</ref>
<ref id="ref66">
<label>66</label><mixed-citation publication-type="other" xlink:type="simple"> Young, L. H., Benson, D. R., Kameel, F. R., Pierce, J. R., Junninen, H., Kulmala, M., and Lee, S.-H.: Laboratory studies of H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;/H&lt;sub&gt;2&lt;/sub&gt;O binary homogeneous nucleation from the SO&lt;sub&gt;2&lt;/sub&gt;+OH reaction: evaluation of the experimental setup and preliminary results, Atmos. Chem. Phys., 8, 4997â€“5016, http://dx.doi.org/10.5194/acp-8-4997-2008doi:10.5194/acp-8-4997-2008, 2008. </mixed-citation>
</ref>
<ref id="ref67">
<label>67</label><mixed-citation publication-type="other" xlink:type="simple"> Zasypkin, A., Grigor&apos;eva, V., Korchak, V., and Gerschenson, Y.: A formula for summing of kinetic resistances for mobile and stationary media: I. Cylindrical reactor, Kin. Catalys., 38, 842â€“851, 1997. </mixed-citation>
</ref>
</ref-list>
</back>
</article>