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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>GÃ¶ttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/acp-11-8157-2011</article-id>
<title-group>
<article-title>Gaseous pollutants in Beijing urban area during the heating period 2007â€“2008: variability, sources, meteorological, and chemical impacts</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Lin</surname>
<given-names>W.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Xu</surname>
<given-names>X.</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>Ge</surname>
<given-names>B.</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>Liu</surname>
<given-names>X.</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Key Laboratory for Atmospheric Chemistry, Centre for Atmosphere Watch &amp; Services, Chinese Academy of Meteorological Sciences, Beijing 100081, China</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>LAPC/NZC, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing 100029, China</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Wuhan Central Meteorological Observatory, Wuhan 430074, China</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>CMA Meteorological Observation Centre, Beijing 100081, China</addr-line>
</aff>
<pub-date pub-type="epub">
<day>10</day>
<month>08</month>
<year>2011</year>
</pub-date>
<volume>11</volume>
<issue>15</issue>
<fpage>8157</fpage>
<lpage>8170</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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<self-uri xlink:href="http://www.atmos-chem-phys.net/11/8157/2011/acp-11-8157-2011.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/8157/2011/acp-11-8157-2011.pdf</self-uri>
<abstract>
<p>Gaseous pollutants, NO&lt;sub&gt;y&lt;/sub&gt;/NO&lt;sub&gt;x&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt;, CO, and O&lt;sub&gt;3&lt;/sub&gt;, were
measured at an urban site in Beijing from 17 November  2007 to 15 March
2008. The average concentrations (with  &amp;plusmn; 1&amp;sigma;) of NO, NO&lt;sub&gt;2&lt;/sub&gt;,
NO&lt;sub&gt;x&lt;/sub&gt;, NO&lt;sub&gt;y&lt;/sub&gt;, CO, SO&lt;sub&gt;2&lt;/sub&gt;, and O&lt;sub&gt;3&lt;/sub&gt; were 29.0 &amp;plusmn;  2.7 ppb,
33.7 &amp;plusmn;  1.4 ppb, 62.7 &amp;plusmn;  4.0 ppb, 72.8 &amp;plusmn;  4.5 ppb, 1.99 &amp;plusmn;  0.13 ppm,
31.9 &amp;plusmn;  2.0 ppb, and 11.9 &amp;plusmn;  0.8 ppb, respectively, with hourly maxima of
200.7 ppb, 113.5 ppb, 303.9 ppb, 323.2 ppb, 15.06 ppm, 147.3 ppb, and
69.7 ppb, respectively. The concentrations of the pollutants show &quot;saw-toothed&quot;
patterns, which are attributable mainly to changes in wind direction and
speed. The frequency distributions of the hourly mean concentrations of
NO&lt;sub&gt;y&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt;, CO, and O&lt;sub&gt;3&lt;/sub&gt; can all be decomposed in the two Lorentz
curves, with their peak concentrations representing background levels under
different conditions. During the observation period, the average ratio
NO&lt;sub&gt;x&lt;/sub&gt;/NO&lt;sub&gt;y&lt;/sub&gt; was 0.86 &amp;plusmn;  0.10, suggesting that the gaseous pollutants
in Beijing in winter are mainly from local emissions. Data of O&lt;sub&gt;3&lt;/sub&gt;,
NO&lt;sub&gt;z&lt;/sub&gt;, and NO&lt;sub&gt;x&lt;/sub&gt;/NO&lt;sub&gt;y&lt;/sub&gt; indicate that photochemistry can take place
in Beijing even in the cold winter period. Based on the measurements of
O&lt;sub&gt;3&lt;/sub&gt;, NO&lt;sub&gt;x&lt;/sub&gt;, and NO&lt;sub&gt;y&lt;/sub&gt;, ozone production efficiency (OPE) is
estimated to be in the range of 0â€“8.9 (ppb ppb&lt;sup&gt;âˆ’1&lt;/sup&gt;) with the mean(&amp;plusmn; 1&amp;sigma;) 
and median values being 1.1(&amp;plusmn; 1.6) and 0.5 (ppb ppb&lt;sup&gt;âˆ’1&lt;/sup&gt;), respectively,
for the winter 2007â€“2008 in Beijing. This low OPE would cause a
photochemical O&lt;sub&gt;3&lt;/sub&gt; source of 5 ppb day&lt;sup&gt;âˆ’1&lt;/sup&gt;, which is small but significant
for surface O&lt;sub&gt;3&lt;/sub&gt; in winter in Beijing. Downward transport of O&lt;sub&gt;3&lt;/sub&gt;-rich
air from the free troposphere is the more important factor for the
enhancement of the O&lt;sub&gt;3&lt;/sub&gt; level in the surface layer, while high NO level
for the destruction of O&lt;sub&gt;3&lt;/sub&gt;. The concentrations of SO&lt;sub&gt;2&lt;/sub&gt;, CO, and
NO&lt;sub&gt;x&lt;/sub&gt; are strongly correlated among each other, indicating that they are
emitted by some common sources. Multiple linear regression analysis is
applied to the concentrations of NO&lt;sub&gt;y&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt;, and CO and empirical
equations are obtained for the NO&lt;sub&gt;y&lt;/sub&gt; concentration. Based the
equations, the relative contributions from mobile and point sources to
NO&lt;sub&gt;y&lt;/sub&gt; is estimated to be 66 &amp;plusmn;  30 % and 40 &amp;plusmn;  16 %, respectively,
suggesting that even in the heating period, mobile sources in Beijing
contribute more to NO&lt;sub&gt;y&lt;/sub&gt; than point sources.</p>
</abstract>
<counts><page-count count="14"/></counts>
</article-meta>
</front>
<body/>
<back>
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