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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-8-2977-2008</article-id>
<title-group>
<article-title>Assessing positive matrix factorization model fit: a new method to estimate uncertainty and bias in factor contributions at the daily time scale</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Hemann</surname>
<given-names>J. G.</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>Brinkman</surname>
<given-names>G. L.</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>Dutton</surname>
<given-names>S. J.</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>Hannigan</surname>
<given-names>M. P.</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>Milford</surname>
<given-names>J. 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>Miller</surname>
<given-names>S. L.</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Department of Applied Mathematics, University of Colorado, Boulder, USA</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Department of Mechanical Engineering, University of Colorado, Boulder, USA</addr-line>
</aff>
<pub-date pub-type="epub">
<day>14</day>
<month>02</month>
<year>2008</year>
</pub-date>
<volume>8</volume>
<issue>1</issue>
<fpage>2977</fpage>
<lpage>3026</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/8/2977/2008/acpd-8-2977-2008.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/8/2977/2008/acpd-8-2977-2008.pdf</self-uri>
<abstract>
<p>A Positive Matrix Factorization receptor model for aerosol pollution source
apportionment was fit to a synthetic dataset simulating one year of daily
measurements of ambient PM&lt;sub&gt;2.5&lt;/sub&gt; concentrations, comprised of 39 chemical
species from nine pollutant sources. A novel method was developed to
estimate model fit uncertainty and bias at the daily time scale, as related
to factor contributions. A balanced bootstrap is used to create replicate
datasets, with the same model then fit to the data. Neural networks are
trained to classify factors based upon chemical profiles, as opposed to
correlating contribution time series, and this classification is used to
align factor orderings across results associated with the replicate
datasets. Factor contribution uncertainty is assessed from the distribution
of results associated with each factor. Comparing modeled factors with input
factors used to create the synthetic data assesses bias. The results
indicate that variability in factor contribution estimates does not
necessarily encompass model error: contribution estimates can have small
associated variability yet also be very biased. These results are likely
dependent on characteristics of the data.</p>
</abstract>
<counts><page-count count="50"/></counts>
</article-meta>
</front>
<body/>
<back>
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