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<front>
<journal-meta>
<journal-id journal-id-type="publisher">ACP</journal-id>
<journal-title-group>
<journal-title>Atmospheric Chemistry and Physics</journal-title>
<abbrev-journal-title abbrev-type="publisher">ACP</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">1680-7324</issn>
<publisher><publisher-name>Copernicus GmbH</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/acp-6-2453-2006</article-id>
<title-group>
<article-title>Kinetics and mechanism of heterogeneous oxidation of sulfur dioxide  by ozone on surface of calcium carbonate</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Li</surname>
<given-names>L.</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>Chen</surname>
<given-names>Z. M.</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>Zhang</surname>
<given-names>Y. H.</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>Zhu</surname>
<given-names>T.</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>Li</surname>
<given-names>J. L.</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>Ding</surname>
<given-names>J.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>State Key Joint Laboratory of Environment Simulation and Pollution  Control, College of Environmental Sciences, Peking University, Beijing 100871, China</addr-line>
</aff>
<pub-date pub-type="epub">
<day>29</day>
<month>06</month>
<year>2006</year>
</pub-date>
<volume>6</volume>
<issue>9</issue>
<fpage>2453</fpage>
<lpage>2464</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>
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<abstract>
<p>Sulfate particles play a key role in the air quality and the global
climate, but the heterogeneous formation mechanism of sulfates on
surfaces of atmospheric particles is not well established.
Carbonates, which act as a reactive component in mineral dust due to
their special chemical properties, may contribute significantly to
the sulfate formation by heterogeneous processes. This paper
presents a study on the oxidation of SO&lt;sub&gt;2&lt;/sub&gt; by O&lt;sub&gt;3&lt;/sub&gt; on
CaCO&lt;sub&gt;3&lt;/sub&gt; particles. Using Diffuse Reflectance Infrared Fourier
Transform Spectroscopy (DRIFTS), the formation of sulfite and
sulfate on the surface was identified, and the roles of O&lt;sub&gt;3&lt;/sub&gt; and
water in oxidation processes were determined. The results showed
that in the presence of O&lt;sub&gt;3&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt;can be oxidized to sulfate
on the surface of CaCO&lt;sub&gt;3&lt;/sub&gt; particles. The reaction is first order
in SO&lt;sub&gt;2&lt;/sub&gt; and zero order in O&lt;sub&gt;3&lt;/sub&gt;. The reactive uptake
coefficient for SO&lt;sub&gt;2&lt;/sub&gt; [(0.6&amp;ndash;9.8)&amp;times;10&lt;sup&gt;14&lt;/sup&gt; molecule
cm&lt;sup&gt;-3&lt;/sup&gt;] oxidation by O&lt;sub&gt;3&lt;/sub&gt; [(1.2&amp;ndash;12)&amp;times;10&lt;sup&gt;14&lt;/sup&gt;
molecule cm&lt;sup&gt;-3&lt;/sup&gt;] was determined to be
(1.4&amp;plusmn;0.3)&amp;times;10&lt;sup&gt;-7&lt;/sup&gt; using the BET area as the
reactive area and (7.7&amp;plusmn;1.6)&amp;times;10&lt;sup&gt;-4&lt;/sup&gt; using the
geometric area. A two-stage mechanism that involves adsorption of
SO&lt;sub&gt;2&lt;/sub&gt; followed by O&lt;sub&gt;3&lt;/sub&gt; oxidation is proposed and the
adsorption of SO&lt;sub&gt;2&lt;/sub&gt; on the CaCO&lt;sub&gt;3&lt;/sub&gt; surface is the
rate-determining step. The proposed mechanism can well explain the
experiment results. The atmospheric implications were explored based
on a box model calculation. It was found that the heterogeneous
reaction might be an important pathway for sulfate formation in the
atmosphere.</p>
</abstract>
<counts><page-count count="12"/></counts>
</article-meta>
</front>
<body/>
<back>
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