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<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-10-26677-2010</article-id>
<title-group>
<article-title>Summer and winter variations of dicarboxylic acids, fatty acids and benzoic acid in PM&lt;sub&gt;2.5&lt;/sub&gt; in Pearl Delta River Region, China</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Ho</surname>
<given-names>K. F.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Ho</surname>
<given-names>S. S. 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>Lee</surname>
<given-names>S. C.</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>Kawamura</surname>
<given-names>K.</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>Zou</surname>
<given-names>S. C.</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Cao</surname>
<given-names>J. J.</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>Xu</surname>
<given-names>H. M.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>SKLLQG, Inst. of Earth Environment Chinese Academy of Sciences, Xi&apos;an, 710075, China</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Research Center of Urban Environmental Technology and Management, Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon,  Hong Kong, China</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Institute of Low Temperature Science Hokkaido University, Sapporo, Japan</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Department of Chemistry, Sun Yat-Sen University, Guangzhou, China</addr-line>
</aff>
<pub-date pub-type="epub">
<day>08</day>
<month>11</month>
<year>2010</year>
</pub-date>
<volume>10</volume>
<issue>11</issue>
<fpage>26677</fpage>
<lpage>26703</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>Ground-based PM&lt;sub&gt;2.5&lt;/sub&gt; samples collected in Pearl River Delta (PRD) region
during winter and summer (from 14 December 2006 to 28 January 2007 in winter
and from 4 July 2007 to 9 August 2007 in summer) were analyzed for 30
water-soluble organic species, including dicarboxylic acids, ketocarboxylic
acids and dicarbonyls, nine fatty acids, and benzoic acid. Molecular
distributions of dicarboxylic acids demonstrated that oxalic acid (C&lt;sub&gt;2&lt;/sub&gt;)
was the most abundant species followed by phthalic acid (Ph) in PRD region.
The concentrations of total dicarboxylic acids ranged from 99 to 1340 ng m&lt;sup&gt;âˆ’3&lt;/sup&gt;, with an average of 438 Â± 267 ng m&lt;sup&gt;âˆ’3&lt;/sup&gt; in PRD. The
concentrations of total ketocarboxylic acids ranged from 0.6 to 207 ng m&lt;sup&gt;âˆ’3&lt;/sup&gt; (43 Â± 48 ng m&lt;sup&gt;âˆ’3&lt;/sup&gt; on average) while the concentrations of
total &amp;alpha;-dicarbonyls, including glyoxal and methylglyoxal, ranged
from 0.2 to 89 ng m&lt;sup&gt;âˆ’3&lt;/sup&gt;, with an average of 11 Â± 18 ng m&lt;sup&gt;âˆ’3&lt;/sup&gt; in
PRD. The total quantified water-soluble organic carbon (TQWOC)
accounted for 3.4 Â± 2.2% of OC and 14.3 Â± 10.3% of water-soluble
OC (WSOC). Hexadecanoic acid (C&lt;sub&gt;16:0&lt;/sub&gt;), octadecanoic acid (C&lt;sub&gt;18:0&lt;/sub&gt;)
and oleic acid (C&lt;sub&gt;18:1&lt;/sub&gt;) are the three most abundant fatty acids in PRD.
The distributions of fatty acids are characterized by a strong even carbon
number predominance with a maximum (C&lt;sub&gt;max&lt;/sub&gt;) at hexadecanoic acid
(C&lt;sub&gt;16:0&lt;/sub&gt;). Ratio of C&lt;sub&gt;18:1&lt;/sub&gt; to C&lt;sub&gt;18:0&lt;/sub&gt; acts as an indicator for
aerosol aging. In PRD, an average of C&lt;sub&gt;18:1&lt;/sub&gt;/C&lt;sub&gt;18:0&lt;/sub&gt; ratio was
0.53 Â± 0.39, suggesting an enhanced photochemical degradation of
unsaturated fatty acid. Seasonal variations of the pollutant concentrations
were found in the four sampling cities. Higher concentrations of TQWOC were
observed in winter (544 ng m&lt;sup&gt;âˆ’3&lt;/sup&gt;) than in summer (318 ng m&lt;sup&gt;âˆ’3&lt;/sup&gt;).
However, the abundances of TQWOC in OC mass were higher in summer
(1.8â€“12.4%, 5.4% on average) than in winter (1.1â€“5.7, 2.6% on
average), being consistent with enhanced secondary production of
dicarboxylic acids in warmer weather. Spatial variations of water-soluble
dicarboxylic acids were characterized by higher concentrations in Hong Kong
and lower concentrations Guangzhou (GZ)/Zhaoqing (ZQ) during winter whereas
highest concentrations were observed in GZ/ZQ during summer. These spatial
and seasonal distributions are consistent with photochemical production and
the subsequent accumulation under different meteorological conditions.</p>
</abstract>
<counts><page-count count="27"/></counts>
</article-meta>
</front>
<body/>
<back>
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