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<article language="en">
	<journal>
		<journal_title>Atmospheric Chemistry and Physics Discussions</journal_title>
		<journal_url>www.atmos-chem-phys-discuss.net</journal_url>
		<issn>1680-7367</issn>
		<eissn>1680-7375</eissn>
		<volume_number>10</volume_number>
		<issue_number>4</issue_number>
		<publication_year>2010</publication_year>
	</journal>
	<doi>10.5194/acpd-10-8765-2010</doi>
	<article_url>http://www.atmos-chem-phys-discuss.net/10/8765/2010/</article_url>
	<abstract_html>http://www.atmos-chem-phys-discuss.net/10/8765/2010/acpd-10-8765-2010.html</abstract_html>
	<fulltext_pdf>http://www.atmos-chem-phys-discuss.net/10/8765/2010/acpd-10-8765-2010.pdf</fulltext_pdf>
	<start_page>8765</start_page>
	<end_page>8810</end_page>
	<publication_date>2010-04-07</publication_date>
	<article_title content_type="html">Single particle characterization of black carbon aerosols at a tropospheric alpine site in Switzerland</article_title>
	<authors>
		<author numeration="1" affiliations="1">
			<name>D. Liu</name>
			<email>dantong.liu@postgrad.manchester.ac.uk</email>
		</author>
		<author numeration="2" affiliations="1">
			<name>M. Flynn</name>
		</author>
		<author numeration="3" affiliations="2">
			<name>M. Gysel</name>
		</author>
		<author numeration="4" affiliations="1">
			<name>A. Créso Targino</name>
		</author>
		<author numeration="5" affiliations="1">
			<name>I. Crawford</name>
		</author>
		<author numeration="6" affiliations="1">
			<name>K. Bower</name>
		</author>
		<author numeration="7" affiliations="1">
			<name>T. Choularton</name>
		</author>
		<author numeration="8" affiliations="2">
			<name>Z. Juranyi</name>
		</author>
		<author numeration="9" affiliations="3">
			<name>M. Steinbacher</name>
		</author>
		<author numeration="10" affiliations="3">
			<name>C. Hüglin</name>
		</author>
		<author numeration="11" affiliations="4">
			<name>J. Curtius</name>
		</author>
		<author numeration="12" affiliations="4">
			<name>M. Kampus</name>
		</author>
		<author numeration="13" affiliations="5">
			<name>A. Petzold</name>
		</author>
		<author numeration="14" affiliations="2">
			<name>E. Weingartner</name>
		</author>
		<author numeration="15" affiliations="2">
			<name>U. Baltensperger</name>
		</author>
		<author numeration="16" affiliations="1">
			<name>H. Coe</name>
		</author>
	</authors>
	<affiliations>
		<affiliation numeration="1" content_type="html">Centre for Atmospheric Science, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, M13 9PL, UK</affiliation>
		<affiliation numeration="2" content_type="html">Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland</affiliation>
		<affiliation numeration="3" content_type="html">EMPA Überlandstrasse 129, 8600 Dübendorf, Switzerland</affiliation>
		<affiliation numeration="4" content_type="html">Institute for Atmospheric Physics, Johannes Gutenberg University, Mainz, Germany</affiliation>
		<affiliation numeration="5" content_type="html">Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, 82234 Wessling, Germany</affiliation>
	</affiliations>
	<abstract content_type="html">Black carbon (BC) mass, size distribution and mixing state in sub-micron
aerosols were characterized from late February to March 2007 using a single
particle incandescence method at the high alpine research station
Jungfraujoch (JFJ), Switzerland (46.33&amp;deg; N, 7.59&amp;deg; E, 3580 m a.s.l.).
JFJ is a ground based location, which is at times exposed to continental
free tropospheric air. A median mass absorption coefficient (MAC) of
10.2&amp;plusmn;3.2 m&lt;sup&gt;2&lt;/sup&gt; g&lt;sup&gt;&amp;minus;1&lt;/sup&gt; at λ = 630 nm was derived by comparing
single particle incandescence measurements of black carbon mass with
continuous measurements of absorption coefficient. This value is comparable
with other estimates at this location. The aerosols measured at the site
were mostly well mixed and aged during transportation via the free
troposphere. Pollutant sources were traced by air mass back trajectories,
trace gases concentrations and the mass loading of BC. In southeasterly wind
directions, mixed or convective weather types provided the potential to vent
polluted boundary layer air from the southern Alpine area and industrial
northern Italy, delivering enhanced BC mass loading and CN concentrations to
the JFJ. The aerosol loadings at this site were also significantly
influenced by precipitation, which led to the removal of BC from the
atmosphere. Precipitation events were shown to remove about 65% of the BC
mass from the free tropospheric background reducing the mean loading from
10&amp;plusmn;5 ngm&lt;sup&gt;&amp;minus;3&lt;/sup&gt; to 4&amp;plusmn;2 ngm&lt;sup&gt;&amp;minus;3&lt;/sup&gt;. Overall, 40&amp;plusmn;15% of the
observed BC particles within the detectable size range were mixed with large
amounts of non-refractory materials present as a thick coating around the BC
core. The growth of particle size into the accumulation mode was positively
linked with the degree of BC mixing, suggesting the important role of
condensable materials in increasing particle size as well as enhancing BC
mixing state. It is the first time that BC mass, size distribution and
mixing state are reported in the free troposphere over Europe. These ground
based measurements also provide the first temporal study of BC in the
European free troposphere quantitatively measured by single particle
methods. At the present time there is only limited information of BC and its
mixing state in the free troposphere, especially above Europe. The results
reported in this paper provide an important constraint on modelled
representation of BC.</abstract>
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</article>

