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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>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/acpd-8-14273-2008</article-id>
<title-group>
<article-title>Emissions of volatile organic compounds inferred from airborne flux measurements over a megacity</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Karl</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>Apel</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>Hodzic</surname>
<given-names>A.</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>Riemer</surname>
<given-names>D.</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>Blake</surname>
<given-names>D.</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>Wiedinmyer</surname>
<given-names>C.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>National Center for Atmospheric Research, Boulder, CO, USA</addr-line>
</aff>
<pub-date pub-type="epub">
<day>25</day>
<month>07</month>
<year>2008</year>
</pub-date>
<volume>8</volume>
<issue>4</issue>
<fpage>14273</fpage>
<lpage>14309</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-discuss.net/8/14273/2008/acpd-8-14273-2008.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/8/14273/2008/acpd-8-14273-2008.pdf</self-uri>
<abstract>
<p>Toluene and benzene are used for assessing the ability to measure disjunct
eddy covariance (DEC) fluxes of Volatile Organic Compounds (VOC) using Proton
Transfer Reaction Mass Spectrometry (PTR-MS) on aircraft. Statistically
significant correlation between vertical wind speed and mixing ratios
suggests that airborne VOC eddy covariance (EC) flux measurements using
PTR-MS are feasible. City-average midday toluene and benzene fluxes are
calculated to be on the order of 15.5&amp;plusmn;4.0 mg/m&lt;sup&gt;2&lt;/sup&gt;/h and
4.7&amp;plusmn;2.3 mg/m&lt;sup&gt;2&lt;/sup&gt;/h respectively. These values argue for an
underestimation of toluene and benzene emissions in current inventories used
for the Mexico City Metropolitan Area (MCMA). Wavelet analysis of
instantaneous toluene and benzene measurements during city overpasses is
tested as a tool to assess surface emission heterogeneity. High toluene to
benzene flux ratios above an industrial district (e.g. 10–15) including the
International airport (e.g. 3–5) and a mean flux (concentration) ratio of
3.2&amp;plusmn;0.5 (3.9&amp;plusmn;0.3) across Mexico City indicate that evaporative
fuel and industrial emissions play an important role for the prevalence of
aromatic compounds. Based on a tracer model, which was constrained by BTEX
(Benzene/Toluene/Ethylbenzene/m,p,o-Xylenes) compound concentration ratios,
the fuel marker methyl-tertiary-butyl-ether (MTBE) and the biomass burning
marker acetonitrile (CH&lt;sub&gt;3&lt;/sub&gt;CN), we show that a combination of industrial,
evaporative fuel, and exhaust emissions account for &amp;gt;90% of all BTEX
sources. Our observations suggest that biomass burning emissions play a minor
role for the abundance of BTEX compounds (0–10%) in the MCMA.</p>
</abstract>
<counts><page-count count="37"/></counts>
</article-meta>
</front>
<body/>
<back>
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