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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>
<abbrev-journal-title abbrev-type="nlm-ta">Atmos. Chem. Phys.</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">1680-7324</issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/acp-14-8419-2014</article-id>
<title-group>
<article-title>Distinguishing molecular characteristics of aerosol water soluble organic matter from the 2011 trans-North Atlantic US GEOTRACES cruise</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Wozniak</surname>
<given-names>A. S.</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>Willoughby</surname>
<given-names>A. S.</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>Gurganus</surname>
<given-names>S. C.</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>Hatcher</surname>
<given-names>P. G.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Department of Chemistry &amp; Biochemistry, Old Dominion University, Norfolk, VA 23529, USA</addr-line>
</aff>
<pub-date pub-type="epub">
<day>21</day>
<month>08</month>
<year>2014</year>
</pub-date>
<volume>14</volume>
<issue>16</issue>
<fpage>8419</fpage>
<lpage>8434</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2014 A. S. Wozniak et al.</copyright-statement>
<copyright-year>2014</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/3.0/">https://creativecommons.org/licenses/by/3.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://acp.copernicus.org/articles/14/8419/2014/acp-14-8419-2014.html">This article is available from https://acp.copernicus.org/articles/14/8419/2014/acp-14-8419-2014.html</self-uri>
<self-uri xlink:href="https://acp.copernicus.org/articles/14/8419/2014/acp-14-8419-2014.pdf">The full text article is available as a PDF file from https://acp.copernicus.org/articles/14/8419/2014/acp-14-8419-2014.pdf</self-uri>
<abstract>
<p>The molecular characteristics of aerosol organic matter (OM) determines to a
large extent its impacts on the atmospheric radiative budget and ecosystem
function in terrestrial and aquatic environments, yet the OM molecular
details of aerosols from different sources are not well established. Aerosol
particulate samples with North American-influenced, North African-influenced,
and marine (minimal recent continental influence) air mass back trajectories
were collected as part of the 2011 trans-North Atlantic US GEOTRACES cruise
and analyzed for their water soluble OM (WSOM) molecular characteristics
using electrospray ionization Fourier transform ion cyclotron resonance mass
spectrometry. Principal component analysis (PCA) separated the samples into
five groups defined by distinct molecular formula characteristics. An
abundance of nitrogen containing compounds with molecular formulas consistent
with amino acid derivatives defined the two samples comprising the primary
marine group (henceforth referred to as Primary Marine), which suggest a
primary marine biological source to their WSOM in spite of their North
American-influenced air mass trajectories. A second group of samples (aged
marine, henceforth referred to as Aged Marine) with marine air mass
trajectories was characterized by an abundance of low O / C (0.15–0.45)
sulfur containing compounds consistent with organosulfate compounds formed
via secondary aging reactions in the atmosphere. Several samples having North
American-influenced air mass trajectories formed another group again
characterized by organosulfate and nitrooxyorganosulfate type compounds with
higher O / C ratios (0.5–1.0) than the Aged Marine samples reflecting the
combustion influence from the North American continent. All the samples with
North African-influenced air mass trajectories were grouped together in the
PCA and were characterized by a lack of heteroatom (N, S, P) containing
molecular formulas covering a wide O / C range (0.15–0.90) reflecting the
desert source of this WSOM. The two marine groups showed molecular formulas
that, on average, had higher H / C ratios and lower O / C ratios and
modified aromaticity indices than the two continentally influenced groups,
which suggests that these properties are characteristic of marine vs.
continental aerosol WSOM. The final sample group, the mixed source samples
(henceforth referred to as Mixed Source), showed intermediate molecular
characteristics, which suggests no dominant continental or marine source. The
source-specific OM details described here will aid efforts to link aerosol OM
source with molecular characteristics and impacts in the environment.</p>
</abstract>
<counts><page-count count="16"/></counts>
</article-meta>
</front>
<body/>
<back>
<ref-list>
<title>References</title>
<ref id="ref1">
<label>1</label><mixed-citation publication-type="other" xlink:type="simple">Aller, J. Y., Kuznetsova, M. R., Jahns, C. J., and Kemp, P. F.: The sea surface microlayer as a source of viral and bacterial enrichment in marine aerosols, J. Aerosol Sci., 36, 801–812, 2005.</mixed-citation>
</ref>
<ref id="ref2">
<label>2</label><mixed-citation publication-type="other" xlink:type="simple">Altieri, K. E., Turpin, B. J., and Seitzinger, S. P.: Oligomers, organosulfates, and nitrooxy organosulfates in rainwater identified by ultra-high resolution electrospray ionization FT-ICR mass spectrometry, Atmos. Chem. Phys., 9, 2533-2542, 2009.</mixed-citation>
</ref>
<ref id="ref3">
<label>3</label><mixed-citation publication-type="other" xlink:type="simple">Altieri, K. E., Hastings, M. G., Peters, A. J., and Sigman, D. M.: Molecular characterization of water soluble organic nitrogen in marine rainwater by ultra-high resolution electrospray ionization mass spectrometry, Atmos. Chem. Phys., 12, 3557–3571, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-12-3557-2012&quot;&gt;https://doi.org/10.5194/acp-12-3557-2012&lt;/a&gt;, 2012.</mixed-citation>
</ref>
<ref id="ref4">
<label>4</label><mixed-citation publication-type="other" xlink:type="simple">Andreae, M. O. and Gelencsér, A.: Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols, Atmos. Chem. Phys., 6, 3131–3148, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-6-3131-2006&quot;&gt;https://doi.org/10.5194/acp-6-3131-2006&lt;/a&gt;, 2006.</mixed-citation>
</ref>
<ref id="ref5">
<label>5</label><mixed-citation publication-type="other" xlink:type="simple">Arimoto, R., Duce, R., Ray, B., Ellis, W., Cullen, J., and Merrill, J.: Trace elements in the atmosphere over the North Atlantic, J. Geophys. Res.-Atmos., 100, 1199–1213, 1995.</mixed-citation>
</ref>
<ref id="ref6">
<label>6</label><mixed-citation publication-type="other" xlink:type="simple">Baker, A. and Croot, P.: Atmospheric and marine controls on aerosol iron solubility in seawater, Mar. Chem., 120, 4–13, 2010.</mixed-citation>
</ref>
<ref id="ref7">
<label>7</label><mixed-citation publication-type="other" xlink:type="simple">Baker, A., Jickells, T., Witt, M., and Linge, K.: Trends in the solubility of iron, aluminium, manganese and phosphorus in aerosol collected over the Atlantic Ocean, Mar. Chem., 98, 43–58, 2006.</mixed-citation>
</ref>
<ref id="ref8">
<label>8</label><mixed-citation publication-type="other" xlink:type="simple">Bianchi, T. S. and Canuel, E. A.: Chemical Biomarkers in Aquatic Ecosystems, Princeton University Press, Princeton, N. J., 2011.</mixed-citation>
</ref>
<ref id="ref9">
<label>9</label><mixed-citation publication-type="other" xlink:type="simple">Booth, B. B., Dunstone, N. J., Halloran, P. R., Andrews, T., and Bellouin, N.: Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability, Nature, 484, 228–232, 2012.</mixed-citation>
</ref>
<ref id="ref10">
<label>10</label><mixed-citation publication-type="other" xlink:type="simple">Brook, R.: Cardiovascular effects of air pollution, Clin. Sci., 115, 175–187, 2008.</mixed-citation>
</ref>
<ref id="ref11">
<label>11</label><mixed-citation publication-type="other" xlink:type="simple">Carlton, A. G., Pinder, R. W., Bhave, P. V., and Pouliot, G. A.: To what extent can biogenic SOA be controlled?, Environ. Sci. Technol., 44, 3376–3380, 2010.</mixed-citation>
</ref>
<ref id="ref12">
<label>12</label><mixed-citation publication-type="other" xlink:type="simple">Chan, M. N. and Chan, C. K.: Mass transfer effects in hygroscopic measurements of aerosol particles, Atmos. Chem. Phys., 5, 2703–2712, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-5-2703-2005&quot;&gt;https://doi.org/10.5194/acp-5-2703-2005&lt;/a&gt;, 2005.</mixed-citation>
</ref>
<ref id="ref13">
<label>13</label><mixed-citation publication-type="other" xlink:type="simple">Charlson, R., Schwartz, S., Hales, J., Cess, R., Coakley, J. J., Hansen, J., and Hofmann, D.: Climate Forcing by Anthropogenic Aerosols, Science, 255, 423–430, 1992.</mixed-citation>
</ref>
<ref id="ref14">
<label>14</label><mixed-citation publication-type="other" xlink:type="simple">Claeys, M., Wang, W., Vermeylen, R., Kourtchev, I., Chi, X., Farhat, Y., Surratt, J. D., Gómez-González, Y., Sciare, J., and Maenhaut, W.: Chemical characterisation of marine aerosol at Amsterdam Island during the austral summer of 2006–2007, J. Aerosol Sci., 41, 13–22, 2010.</mixed-citation>
</ref>
<ref id="ref15">
<label>15</label><mixed-citation publication-type="other" xlink:type="simple">Davidson, C. I., Phalen, R. F., and Solomon, P. A.: Airborne Particulate Matter and Human Health: A Review, Aerosol Sci. Tech., 39, 737–749, 2005.</mixed-citation>
</ref>
<ref id="ref16">
<label>16</label><mixed-citation publication-type="other" xlink:type="simple">Decesari, S., Facchini, M., Matta, E., Mircea, M., Fuzzi, S., Chughtai, A., and Smith, D.: Water soluble organic compounds formed by oxidation of soot, Atmos. Environ., 36, 1827–1832, 2002.</mixed-citation>
</ref>
<ref id="ref17">
<label>17</label><mixed-citation publication-type="other" xlink:type="simple">Decesari, S., Finessi, E., Rinaldi, M., Paglione, M., Fuzzi, S., Stephanou, E. G., Tziaras, T., Spyros, A., Ceburnis, D., O&apos;Dowd, C., Dal&apos;Osto, M., Harris, R. M., Allan, J., Coe, H., and Facchini, M. C.: Primary and secondary marine organic aerosols over the North Atlantic Ocean during the MAP experiment, J. Geophys. Res.-Atmos., 116, D22210, &lt;a href=&quot;http://dx.doi.org/10.1029/2011JD016204&quot;&gt;https://doi.org/10.1029/2011JD016204&lt;/a&gt;, 2011.</mixed-citation>
</ref>
<ref id="ref18">
<label>18</label><mixed-citation publication-type="other" xlink:type="simple">De Gouw, J. A., Brock, C. A., Atlas, E. L., Bates, T. S., Fehsenfeld, F. C., Goldan, P. D., Holloway, J. S., Kuster, W. C., Lerner, B. M., Matthew, B. M., Middlebrook, A. M., Onasch, T. B., Peltier, R. E., Quinn, P. K., Senff, C. J., Stohl, A., Sullivan, A. P., Trainer, M., Warneke, C. Weber, R. J., and Williams, E. J.: Sources of particulate matter in the northeastern United States in summer: 1. Direct emissions and secondary formation of organic matter in urban plumes, J. Geophys. Res., 113, D08301, &lt;a href=&quot;http://dx.doi.org/10.1029/2007JD009243&quot;&gt;https://doi.org/10.1029/2007JD009243&lt;/a&gt;, 2008.</mixed-citation>
</ref>
<ref id="ref19">
<label>19</label><mixed-citation publication-type="other" xlink:type="simple">Dittmar, T., Koch, B., Hertkorn, N., and Kattner, G.: A simple and efficient method for the solid-phase extraction of dissolved organic matter (SPE-DOM) from seawater, Limnol. Oceanogr.-Meth., 6, 230–235, 2008.</mixed-citation>
</ref>
<ref id="ref20">
<label>20</label><mixed-citation publication-type="other" xlink:type="simple">Draxler, R. R.: Evaluation of an ensemble dispersion calculation, J. Appl. Meteorol., 42, 308–317, 2003.</mixed-citation>
</ref>
<ref id="ref21">
<label>21</label><mixed-citation publication-type="other" xlink:type="simple">Draxler, R. R. and Rolph, G.: HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) Model access via NOAA ARL READY Website, &lt;a href=&quot;http://ready.arl.noaa.gov/HYSPLIT.php&quot;&gt;http://ready.arl.noaa.gov/HYSPLIT.php&lt;/a&gt; (last access: July 2013), NOAA Air Resources Laboratory, Silver Spring, MD, 2013.</mixed-citation>
</ref>
<ref id="ref22">
<label>22</label><mixed-citation publication-type="other" xlink:type="simple">Driscoll, C. T., Lawrence, G. B., Bulger, A. J., Butler, T. J., Cronan, C. S., Eagar, C., Lambert, K. F., Likens, G. E., Stoddard, J. L., and Weathers, K. C.: Acidic Deposition in the Northeastern United States: Sources and Inputs, Ecosystem Effects, and Management Strategies, BioScience, 51, 180–198, 2001.</mixed-citation>
</ref>
<ref id="ref23">
<label>23</label><mixed-citation publication-type="other" xlink:type="simple">Duarte, C. M., Dachs, J., Llabrés, M., Alonso-Laita, P., Gasol, J. M., Tovar-Sánchez, A., Sañudo-Wilhemy, S., and Agustí, S.: Aerosol inputs enhance new production in the subtropical northeast Atlantic, J. Geophys. Res., 111, G04006, &lt;a href=&quot;http://dx.doi.org/10.1029/2005JG000140&quot;&gt;https://doi.org/10.1029/2005JG000140&lt;/a&gt;, 2006.</mixed-citation>
</ref>
<ref id="ref24">
<label>24</label><mixed-citation publication-type="other" xlink:type="simple">Duce, R. A. and Tindale, N. W.: Atmospheric transport of iron and its deposition in the ocean, Limnol. Oceanogr., 36, 1715–1726, 1991.</mixed-citation>
</ref>
<ref id="ref25">
<label>25</label><mixed-citation publication-type="other" xlink:type="simple">Eglinton, T. I., Eglinton, G., Dupont, L., Sholkovitz, E. R., Montlucon, D., and Reddy, C. M.: Composition, age, and provenance of organic matter in NW African dust over the Atlantic Ocean, Geochem. Geophys. Geosyst., 3, 1–27, 2002.</mixed-citation>
</ref>
<ref id="ref26">
<label>26</label><mixed-citation publication-type="other" xlink:type="simple">Facchini, M. C., Decesari, S., Rinaldi, M., Carbone, C., Finessi, E., Mircea, M., Fuzzi, S., Moretti, F., Tagliavini, E., Ceburnis, D., and O&apos;Dowd, C. D.: Important source of marine secondary organic aerosol from biogenic amines, Environ. Sci. Technol., 42, 9116–9121, 2008a.</mixed-citation>
</ref>
<ref id="ref27">
<label>27</label><mixed-citation publication-type="other" xlink:type="simple">Facchini, M. C., Rinaldi, M., Decesari, S., Carbone, C., Finessi, E., Mircea, M., Fuzzi, S., Ceburnis, D., Flanagan, R., Nilsson, E. D., de Leeuw, G., Martino, M., Woeltjen, J., and O&apos;Dowd, C. D.: Primary submicron marine aerosol dominated by insoluble organic colloids and aggregates, Geophys. Res. Lett., 35, L17814, &lt;a href=&quot;http://dx.doi.org/10.1029/2008GL034210&quot;&gt;https://doi.org/10.1029/2008GL034210&lt;/a&gt;, 2008b.</mixed-citation>
</ref>
<ref id="ref28">
<label>28</label><mixed-citation publication-type="other" xlink:type="simple">Fagerbakke, K. M., Heldal, M., and Norland, S.: Content of carbon, nitrogen, oxygen, sulfur and phosphorus in native aquatic and cultured bacteria, Aquat. Microb. Ecol., 10, 15–27, 1996.</mixed-citation>
</ref>
<ref id="ref29">
<label>29</label><mixed-citation publication-type="other" xlink:type="simple">Gagosian, R. B., Peltzer, E. T., and Zafiriou, O. C.: Atmospheric transport of continentally derived lipids to the tropical North Pacific, Nature, 291, 312–314, 1981.</mixed-citation>
</ref>
<ref id="ref30">
<label>30</label><mixed-citation publication-type="other" xlink:type="simple">Gantt, B. and Meskhidze, N.: The physical and chemical characteristics of marine primary organic aerosol: a review, Atmos. Chem. Phys., 13, 3979–3996, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-13-3979-2013&quot;&gt;https://doi.org/10.5194/acp-13-3979-2013&lt;/a&gt;, 2013.</mixed-citation>
</ref>
<ref id="ref31">
<label>31</label><mixed-citation publication-type="other" xlink:type="simple">Hallquist, M., Wenger, J. C., Baltensperger, U., Rudich, Y., Simpson, D., Claeys, M., Dommen, J., Donahue, N. M., George, C., Goldstein, A. H., Hamilton, J. F., Herrmann, H., Hoffmann, T., Iinuma, Y., Jang, M., Jenkin, M. E., Jimenez, J. L., Kiendler-Scharr, A., Maenhaut, W., McFiggans, G., Mentel, Th. F., Monod, A., Prévôt, A. S. H., Seinfeld, J. H., Surratt, J. D., Szmigielski, R., and Wildt, J.: The formation, properties and impact of secondary organic aerosol: current and emerging issues, Atmos. Chem. Phys., 9, 5155–5236, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-9-5155-2009&quot;&gt;https://doi.org/10.5194/acp-9-5155-2009&lt;/a&gt;, 2009.</mixed-citation>
</ref>
<ref id="ref32">
<label>32</label><mixed-citation publication-type="other" xlink:type="simple">Hansen, J., Nazarenko, L., Ruedy, R., Sato, M., Willis, J., Del Genio, A., Koch, D., Lacis, A., Lo, K., Menon, S., Novakov, T., Perlwitz, J., Russell, G., Schmidt, G. A., and Tausnev, N.: Earth&apos;s Energy Imbalance: Confirmation and Implications, Science, 308, 1431–1435, 2005.</mixed-citation>
</ref>
<ref id="ref33">
<label>33</label><mixed-citation publication-type="other" xlink:type="simple">Hawkins, L. N. and Russell, L. M.: Polysaccharides, proteins, and phytoplankton fragments: four chemically distinct types of marine primary organic aerosol classified by single particle spectromicroscopy, Adv. Meteor., 2010, 612132, &lt;a href=&quot;http://dx.doi.org/10.1155/2010/612132&quot;&gt;https://doi.org/10.1155/2010/612132&lt;/a&gt;, 2010.</mixed-citation>
</ref>
<ref id="ref34">
<label>34</label><mixed-citation publication-type="other" xlink:type="simple">Hawkins, L. N., Russell, L. M., Covert, D. S., Quinn, P. K., and Bates, T. S.: Carboxylic acids, sulfates, and organosulfates in processed continental organic aerosol over the southeast Pacific Ocean during VOCALS-REx 2008, J. Geophys. Res.-Atmos., 115, D13201, &lt;a href=&quot;http://dx.doi.org/10.1029/2009JD013276&quot;&gt;https://doi.org/10.1029/2009JD013276&lt;/a&gt;, 2010.</mixed-citation>
</ref>
<ref id="ref35">
<label>35</label><mixed-citation publication-type="other" xlink:type="simple">Heald, C. L., Kroll, J. H., Jimenez, J. L., Docherty, K. S., DeCarlo, P. F., Aiken, A. C., Chen, Q., Martin, S. T., Farmer, D. K., and Artaxo, P.: A simplified description of the evolution of organic aerosol composition in the atmosphere, Geophys. Res. Lett., 37, L08803, &lt;a href=&quot;http://dx.doi.org/10.1029/2010GL042737&quot;&gt;https://doi.org/10.1029/2010GL042737&lt;/a&gt;, 2010.</mixed-citation>
</ref>
<ref id="ref36">
<label>36</label><mixed-citation publication-type="other" xlink:type="simple">Hewson, I. and Fuhrmann, J.: Viruses, Bacteria, and the Microbial Loop, in: Nitrogen in the Marine Environment, edited by: Capone, D. G., Bronk, D. A., Mulholland, M. R., and Carpenter, E. J., Academic Press, Burlington, MA, 2008.</mixed-citation>
</ref>
<ref id="ref37">
<label>37</label><mixed-citation publication-type="other" xlink:type="simple">Hockaday, W. C., Grannas, A. M., Kim, S., and Hatcher, P. G.: Direct molecular evidence for the degradation and mobility of black carbon in soils from the ultrahigh-resolution mass spectral analysis of dissolved organic matter from a fire-impacted forest soil, Org. Geochem., 37, 501–510, 2006.</mixed-citation>
</ref>
<ref id="ref38">
<label>38</label><mixed-citation publication-type="other" xlink:type="simple">Iinuma, Y., Muller, C., Berndt, T., Boge, O., Claeys, M., and Herrmann, H.: Evidence for the existence of organosulfates from β-pinene ozonolysis in ambient secondary organic aerosol, Environ. Sci. Technol., 41, 6678–6683, 2007.</mixed-citation>
</ref>
<ref id="ref39">
<label>39</label><mixed-citation publication-type="other" xlink:type="simple">Kanakidou, M., Seinfeld, J. H., Pandis, S. N., Barnes, I., Dentener, F. J., Facchini, M. C., Van Dingenen, R., Ervens, B., Nenes, A., Nielsen, C. J., Swietlicki, E., Putaud, J. P., Balkanski, Y., Fuzzi, S., Horth, J., Moortgat, G. K., Winterhalter, R., Myhre, C. E. L., Tsigaridis, K., Vignati, E., Stephanou, E. G., and Wilson, J.: Organic aerosol and global climate modelling: a review, Atmos. Chem. Phys., 5, 1053–1123, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-5-1053-2005&quot;&gt;https://doi.org/10.5194/acp-5-1053-2005&lt;/a&gt;, 2005.</mixed-citation>
</ref>
<ref id="ref40">
<label>40</label><mixed-citation publication-type="other" xlink:type="simple">Kendrick, E.: A Mass Scale Based on CH&lt;sub&gt;2&lt;/sub&gt; = 14.0000 for High Resolution Mass Spectrometry of Organic Compounds, Anal. Chem., 35, 2146–2154, 1963.</mixed-citation>
</ref>
<ref id="ref41">
<label>41</label><mixed-citation publication-type="other" xlink:type="simple">Koch, B. and Dittmar, T.: From mass to structure: an aromaticity index for high-resolution mass data of natural organic matter, Rapid Commun. Mass Sp., 20, 926–932, 2006.</mixed-citation>
</ref>
<ref id="ref42">
<label>42</label><mixed-citation publication-type="other" xlink:type="simple">Kourtchev, I., Fuller, S. J., Giorio, C., Healy, R. M., Wilson, E., O&apos;Connor, I., Wenger, J. C., McLeod, M., Aalto, J., Ruuskanen, T. M., Maenhaut, W., Jones, R., Venables, D. S., Sodeau, J. R., Kulmala, M., and Kalberer, M.: Molecular composition of biogenic secondary organic aerosols using ultrahigh-resolution mass spectrometry: comparing laboratory and field studies, Atmos. Chem. Phys., 14, 2155–2167, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-14-2155-2014&quot;&gt;https://doi.org/10.5194/acp-14-2155-2014&lt;/a&gt;, 2014.</mixed-citation>
</ref>
<ref id="ref43">
<label>43</label><mixed-citation publication-type="other" xlink:type="simple">Kroll, J. H., Donahue, N. M., Jimenez, J. L., Kessler, S. H., Canagaratna, M. R., Wilson, K. R., Altieri, K. E., Mazzoleni, L. R., Wozniak, A. S., Bluhm, H., Mysak, E. R., Smith, J. D., Kolb, C. E., and Worsnop, D. R.: Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol, Nat. Chem., 3, 133–139, 2011.</mixed-citation>
</ref>
<ref id="ref44">
<label>44</label><mixed-citation publication-type="other" xlink:type="simple">Kujawinski, E. B., Longnecker, K., Blough, N. V., Vecchio, R. D., Finlay, L., Kitner, J. B., and Giovannoni, S. J.: Identification of possible source markers in marine dissolved organic matter using ultrahigh resolution mass spectrometry, Geochim. Cosmochim. Ac., 73, 4384–4399, 2009.</mixed-citation>
</ref>
<ref id="ref45">
<label>45</label><mixed-citation publication-type="other" xlink:type="simple">Kuznetsova, M., Lee, C., and Aller, J.: Characterization of the proteinaceous matter in marine aerosols, Mar. Chem., 96, 359–377, 2005.</mixed-citation>
</ref>
<ref id="ref46">
<label>46</label><mixed-citation publication-type="other" xlink:type="simple">Likens, G. E., Bormann, F. H., Pierce, R. S., Eaton, J. S., and Munn, R. E.: Long-term trends in precipitation chemistry at Hubbard Brook, New Hampshire, Atmos. Environ., 18, 2641–2647, 1984.</mixed-citation>
</ref>
<ref id="ref47">
<label>47</label><mixed-citation publication-type="other" xlink:type="simple">Lin, P., Rincon, A. G., Kalberer, M., and Yu, J. Z.: Elemental composition of HULIS in the Pearl River Delta Region, China: Results inferred from positive and negative electrospray high resolution mass spectrometric data, Environ. Sci. Technol., 46, 7454–7462, 2012.</mixed-citation>
</ref>
<ref id="ref48">
<label>48</label><mixed-citation publication-type="other" xlink:type="simple">Mazzoleni, L. R., Ehrmann, B. M., Shen, X., Marshall, A. G., and Collett Jr., J. L.: Water-Soluble Atmospheric Organic Matter in Fog: Exact Masses and Chemical Formula Identification by Ultrahigh-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Environ. Sci. Technol., 44, 3690–3697, 2010.</mixed-citation>
</ref>
<ref id="ref49">
<label>49</label><mixed-citation publication-type="other" xlink:type="simple">Meskhidze, N., Petters, M. D., Tsigaridis, K., Bates, T., O&apos;Dowd, C., Reid, J., Lewis, E. R., Gantt, B., Anguelova, M. D., Bhave, P. V., Bird, J., Callaghan, A. H., Ceburnis, D., Chang, R., Clarke, A., de Leeuw, G., Deane, G., DeMott, P. J., Elliot, S., Facchini, M. C., Fairall, C. W., Hawkins, L., Hu, Y., Hudson, J. G., Johnson, M. S., Kaku, K. C., Keene, W. C., Kieber, D. J., Long, M. S., Martensson, M., Modini, R. L., Osburn, C. L., Prather, K. A., Pszenny, A., Rinaldi, M., Russell, L. M., Salter, M., Sayer, A. M., Smirnov, A., Suda, S. R., Toth, T. D., Worsnop, D. R., Wozniak, A., and Zorn, S. R.: Production mechanisms, number concentration, size distribution, chemical composition, and optical properties of sea spray aerosols, Atmos. Sci. Lett., 14, 207–213, &lt;a href=&quot;http://dx.doi.org/10.1002/asl2.441&quot;&gt;https://doi.org/10.1002/asl2.441&lt;/a&gt;, 2013.</mixed-citation>
</ref>
<ref id="ref50">
<label>50</label><mixed-citation publication-type="other" xlink:type="simple">Minerath, E. C. and Elrod, M. J.: Assessing the potential for diol and hydroxy sulfate ester formation from the reaction of epoxides in tropospheric aerosols, Environ. Sci. Technol., 43, 1386–1392, 2009.</mixed-citation>
</ref>
<ref id="ref51">
<label>51</label><mixed-citation publication-type="other" xlink:type="simple">Minerath, E. C., Schultz, M. P., and Elrod, M. J.: Kinetics of the reactions of isoprene-derived epoxides in model tropospheric aerosol solutions, Environ. Sci. Technol., 43, 8133–8139, 2009.</mixed-citation>
</ref>
<ref id="ref52">
<label>52</label><mixed-citation publication-type="other" xlink:type="simple">Mitra, S., Wozniak, A. S., Miller, R., Hatcher, P. G., Buonassissi, C., and Brown, M.: Multiproxy probing of rainwater dissolved organic matter (DOM) composition in coastal storms as a function of trajectory, Mar. Chem., 154, 67–76, 2013.</mixed-citation>
</ref>
<ref id="ref53">
<label>53</label><mixed-citation publication-type="other" xlink:type="simple">O&apos;Brien, R. E., Laskin, A., Laskin, J., Liu, S., Weber, R., Russell, L. M., and Goldstein, A. H.: Molecular characterization of organic aerosol using nanospray desorption/electrospray ionization mass spectrometry: CalNex 2010 field study, Atmos. Environ., 68, 265–272, &lt;a href=&quot;http://dx.doi.org/10.1016/j.atmosenv.2012.11.056&quot;&gt;https://doi.org/10.1016/j.atmosenv.2012.11.056&lt;/a&gt;, 2012.</mixed-citation>
</ref>
<ref id="ref54">
<label>54</label><mixed-citation publication-type="other" xlink:type="simple">O&apos;Dowd, C. D. and De Leeuw, G.: Marine aerosol production: a review of the current knowledge, Philos. T. Roy. Soc. A, 365, 1753–1774, 2007.</mixed-citation>
</ref>
<ref id="ref55">
<label>55</label><mixed-citation publication-type="other" xlink:type="simple">Ovadnevaite, J., Ceburnis, D., Martucci, G., Bialek, J., Monahan, C., Rinaldi, M., Facchini, M. C., Berresheim, H., Worsnop, D. R., and O&apos;Dowd, C.: Primary marine organic aerosol: A dichotomy of low hygroscopicity and high CCN activity, Geophys. Res. Lett., 38, L21806, &lt;a href=&quot;http://dx.doi.org/10.1029/2011GL048869&quot;&gt;https://doi.org/10.1029/2011GL048869&lt;/a&gt;, 2011a.</mixed-citation>
</ref>
<ref id="ref56">
<label>56</label><mixed-citation publication-type="other" xlink:type="simple">Ovadnevaite, J., O&apos;Dowd, C., Dall&apos;Osto, M., Ceburnis, D., Worsnop, D. R., and Berresheim, H.: Detecting high contributions of primary organic matter to marine aerosol: A case study, Geophys. Res. Lett., 38, L02807, &lt;a href=&quot;http://dx.doi.org/10.1029/2010GL046083&quot;&gt;https://doi.org/10.1029/2010GL046083&lt;/a&gt;, 2011b.</mixed-citation>
</ref>
<ref id="ref57">
<label>57</label><mixed-citation publication-type="other" xlink:type="simple">Paglione, M., Kiendler-Scharr, A., Mensah, A. A., Finessi, E., Giulianelli, L., Sandrini, S., Facchini, M. C., Fuzzi, S., Schlag, P., Piazzalunga, A., Tagliavini, E., Henzing, J. S., and Decesari, S.: Identification of humic-like substances (HULIS) in oxygenated organic aerosols using NMR and AMS factor analyses and liquid chromatographic techniques, Atmos. Chem. Phys., 14, 25–45, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-14-25-2014&quot;&gt;https://doi.org/10.5194/acp-14-25-2014&lt;/a&gt;, 2014.</mixed-citation>
</ref>
<ref id="ref58">
<label>58</label><mixed-citation publication-type="other" xlink:type="simple">Paris, R. and Desboeufs, K. V.: Effect of atmospheric organic complexation on iron-bearing dust solubility, Atmos. Chem. Phys., 13, 4895–4905, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-13-4895-2013&quot;&gt;https://doi.org/10.5194/acp-13-4895-2013&lt;/a&gt;, 2013.</mixed-citation>
</ref>
<ref id="ref59">
<label>59</label><mixed-citation publication-type="other" xlink:type="simple">Pavlovic, J. and Hopke, P.: Chemical nature and molecular weight distribution of the water-soluble fine and ultrafine PM fractions collected in a rural environment, Atmos. Environ., 59, 264–271, 2012.</mixed-citation>
</ref>
<ref id="ref60">
<label>60</label><mixed-citation publication-type="other" xlink:type="simple">Prospero, J. M.: Saharan dust transport over the North Atlantic Ocean and Mediterranean: An overview, in: The impact of desert dust across the Mediterranean, Springer, the Netherlands, 1996.</mixed-citation>
</ref>
<ref id="ref61">
<label>61</label><mixed-citation publication-type="other" xlink:type="simple">Prospero, J. M.: Assessing the impact of advected African dust on air quality and health in the eastern United States, Hum. Ecol. Risk Assess., 5, 471–479, 1999.</mixed-citation>
</ref>
<ref id="ref62">
<label>62</label><mixed-citation publication-type="other" xlink:type="simple">Ramanathan, V., Crutzen, P. J., Kiehl, J. T., and Rosenfeld, D.: Aerosols, Climate, and the Hydrological Cycle, Science, 294, 2119–2124, 2001.</mixed-citation>
</ref>
<ref id="ref63">
<label>63</label><mixed-citation publication-type="other" xlink:type="simple">Reemtsma, T., These, A., Springer, A., and Linscheid, M.: Fulvic acids as transition state of organic matter: indications from high resolution mass spectrometry, Environ. Sci. Technol., 40, 5839–5845, 2006.</mixed-citation>
</ref>
<ref id="ref64">
<label>64</label><mixed-citation publication-type="other" xlink:type="simple">Rhind, S. M.: Anthropogenic pollutants: a threat to ecosystem sustainability?, Philos. T. Roy. Soc. B, 364, 3391–3401, 2009.</mixed-citation>
</ref>
<ref id="ref65">
<label>65</label><mixed-citation publication-type="other" xlink:type="simple">Rinaldi, M., Fuzzi, S., Decesari, S., Marullo, S., Santoleri, R., Provenzale, A., Hardenberg, J., Ceburnis, D., Vaishya, A., and O&apos;Dowd, C. D.: Is chlorophyll-a the best surrogate for organic matter enrichment in submicron primary marine aerosol?, J. Geophys. Res., 118, 4964–4973, &lt;a href=&quot;http://dx.doi.org/10.1002/jgrd.50417&quot;&gt;https://doi.org/10.1002/jgrd.50417&lt;/a&gt;, 2013.</mixed-citation>
</ref>
<ref id="ref66">
<label>66</label><mixed-citation publication-type="other" xlink:type="simple">Rolph, G.: Real-time Environmental Applications and Display sYstem (READY) Website, &lt;a href=&quot;http://ready.arl.noaa.gov&quot;&gt;http://ready.arl.noaa.gov&lt;/a&gt; (last access: July 2013), NOAA Air Resources Laboratory, Silver Spring, MD, 2013.</mixed-citation>
</ref>
<ref id="ref67">
<label>67</label><mixed-citation publication-type="other" xlink:type="simple">Romero, F. and Oehme, M.: Organosulfates – A New Component of Humic-Like Substances in Atmospheric Aerosols?, J. Atmos. Chem., 52, 283–294, 2005.</mixed-citation>
</ref>
<ref id="ref68">
<label>68</label><mixed-citation publication-type="other" xlink:type="simple">Rossel, P. E., Vähätalo, A. V., Witt, M., and Dittmar, T.: Molecular composition of dissolved organic matter from a wetland plant (Juncus effusus) after photochemical and microbial decomposition (1.25 yr): Common features with deep sea dissolved organic matter, Org. Geochem., 60, 62–71, 2013.</mixed-citation>
</ref>
<ref id="ref69">
<label>69</label><mixed-citation publication-type="other" xlink:type="simple">Russell, L. M., Hawkins, L. N., Frossard, A. A., Quinn, P. K., and Bates, T. S.: Carbohydrate-like composition of submicron atmospheric particles and their production from ocean bubble bursting, P. Natl. Acad. Sci. USA, 107, 6652–6657, 2010.</mixed-citation>
</ref>
<ref id="ref70">
<label>70</label><mixed-citation publication-type="other" xlink:type="simple">Salma, I., Mészáros, T., Maenhaut, W., Vass, E., and Majer, Z.: Chirality and the origin of atmospheric humic-like substances, Atmos. Chem. Phys., 10, 1315–1327, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-10-1315-2010&quot;&gt;https://doi.org/10.5194/acp-10-1315-2010&lt;/a&gt;, 2010.</mixed-citation>
</ref>
<ref id="ref71">
<label>71</label><mixed-citation publication-type="other" xlink:type="simple">Sato, K., Takami, A., Kato, Y., Seta, T., Fujitani, Y., Hikida, T., Shimono, A., and Imamura, T.: AMS and LC/MS analyses of SOA from the photooxidation of benzene and 1,3,5-trimethylbenzene in the presence of NO&lt;i&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/i&gt;: effects of chemical structure on SOA aging, Atmos. Chem. Phys., 12, 4667–4682, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-12-4667-2012&quot;&gt;https://doi.org/10.5194/acp-12-4667-2012&lt;/a&gt;, 2012.</mixed-citation>
</ref>
<ref id="ref72">
<label>72</label><mixed-citation publication-type="other" xlink:type="simple">Schmitt-Kopplin, P., Gelencseìr, A., Dabek-Zlotorzynska, E., Kiss, G., Hertkorn, N., Harir, M., Hong, Y., and Gebefügi, I.: Analysis of the Unresolved Organic Fraction in Atmospheric Aerosols with Ultrahigh-Resolution Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy: Organosulfates As Photochemical Smog Constituents, Anal. Chem., 82, 8017–8026, 2010.</mixed-citation>
</ref>
<ref id="ref73">
<label>73</label><mixed-citation publication-type="other" xlink:type="simple">Schmitt-Kopplin, P., Liger-Belair, G., Koch, B. P., Flerus, R., Kattner, G., Harir, M., Kanawati, B., Lucio, M., Tziotis, D., Hertkorn, N., and Gebefügi, I.: Dissolved organic matter in sea spray: a transfer study from marine surface water to aerosols, Biogeosciences, 9, 1571–1582, &lt;a href=&quot;http://dx.doi.org/10.5194/bg-9-1571-2012&quot;&gt;https://doi.org/10.5194/bg-9-1571-2012&lt;/a&gt;, 2012.</mixed-citation>
</ref>
<ref id="ref74">
<label>74</label><mixed-citation publication-type="other" xlink:type="simple">Shapiro, E. L., Szprengiel, J., Sareen, N., Jen, C. N., Giordano, M. R., and McNeill, V. F.: Light-absorbing secondary organic material formed by glyoxal in aqueous aerosol mimics, Atmos. Chem. Phys., 9, 2289–2300, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-9-2289-2009&quot;&gt;https://doi.org/10.5194/acp-9-2289-2009&lt;/a&gt;, 2009.</mixed-citation>
</ref>
<ref id="ref75">
<label>75</label><mixed-citation publication-type="other" xlink:type="simple">Siefert, R. L., Pehkonen, S. O., Erel, Y., and Hoffmann, M. R.: Iron photochemistry of aqueous suspensions of ambient aerosol with added organic acids, Geochim. Cosmochim. Ac., 58, 3271–3279, 1994.</mixed-citation>
</ref>
<ref id="ref76">
<label>76</label><mixed-citation publication-type="other" xlink:type="simple">Sleighter, R. L. and Hatcher, P. G.: The application of electrospray ionization coupled to ultrahigh resolution mass spectrometry for the molecular characterization of natural organic matter, J. Mass Spectrom., 42, 559–574, 2007.</mixed-citation>
</ref>
<ref id="ref77">
<label>77</label><mixed-citation publication-type="other" xlink:type="simple">Sleighter, R. L. and Hatcher, P. G.: Molecular characterization of dissolved organic matter (DOM) along a river to ocean transect of the lower Chesapeake Bay by ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry, Mar. Chem., 110, 140–152, 2008.</mixed-citation>
</ref>
<ref id="ref78">
<label>78</label><mixed-citation publication-type="other" xlink:type="simple">Sleighter, R. L., McKee, G. A., and Hatcher, P. G.: Direct Fourier transform mass spectral analysis of natural waters with low dissolved organic matter, Org. Geochem., 40, 119–125, 2009.</mixed-citation>
</ref>
<ref id="ref79">
<label>79</label><mixed-citation publication-type="other" xlink:type="simple">Sleighter, R. L., Liu, Z., Xue, J., and Hatcher, P. G.: Multivariate Statistical Approaches for the Characterization of Dissolved Organic Matter Analyzed by Ultrahigh Resolution Mass Spectrometry, Environ. Sci. Technol., 44, 7576–7582, 2010.</mixed-citation>
</ref>
<ref id="ref80">
<label>80</label><mixed-citation publication-type="other" xlink:type="simple">Stone, E. A., Hedman, C. J., Sheesley, R. J., Shafer, M. M., and Schauer, J. J.: Investigating the chemical nature of humic-like substances (HULIS) in North American atmospheric aerosols by liquid chromatography tandem mass spectrometry, Atmos. Environ., 43, 4205–4213, 2009.</mixed-citation>
</ref>
<ref id="ref81">
<label>81</label><mixed-citation publication-type="other" xlink:type="simple">Stubbins, A., Spencer, R. G., Chen, H., Hatcher, P. G., Mopper, K., Hernes, P. J., Mwamba, V. L., Mangangu, A. M., Wabakanghanzi, J. N., and Six, J.: Illuminated darkness: Molecular signatures of Congo River dissolved organic matter and its photochemical alteration as revealed by ultrahigh precision mass spectrometry, Limnol. Oceanogr., 55, 1467–1477, 2010.</mixed-citation>
</ref>
<ref id="ref82">
<label>82</label><mixed-citation publication-type="other" xlink:type="simple">Surratt, J. D., Kroll, J. H., Kleindienst, T. E., Edney, E. O., Claeys, M., Sorooshian, A., Ng, N. L., Offenberg, J. H., Lewandowski, M., Jaoui, M., Flagan, R., and Seinfeld, J. H.: Evidence for Organosulfates in Secondary Organic Aerosol, Environ. Sci. Technol., 41, 517–527, 2007.</mixed-citation>
</ref>
<ref id="ref83">
<label>83</label><mixed-citation publication-type="other" xlink:type="simple">Surratt, J. D., Gómez-González, Y., Chan, A. W., Vermeylen, R., Shahgholi, M., Kleindienst, T. E., Edney, E. O., Offenberg, J. H., Lewandowski, M., Jaoui, M., Maenhaut, W., Claeys, M., Flagan, R., and Seinfeld, J.: Organosulfate Formation in Biogenic Secondary Organic Aerosol, J. Phys. Chem. A, 112, 8345–8378, 2008.</mixed-citation>
</ref>
<ref id="ref84">
<label>84</label><mixed-citation publication-type="other" xlink:type="simple">Tan, K. H.: Humic Matter in Soil and the Environment: Principles and Controversies, Marcel Dekker Inc., New York, 2003.</mixed-citation>
</ref>
<ref id="ref85">
<label>85</label><mixed-citation publication-type="other" xlink:type="simple">Velinsky, D. J., Wade, T. L., and Wong, G. T.: Atmospheric deposition of organic carbon to Chesapeake Bay, Atmos. Environ., 20, 941–947, 1986.</mixed-citation>
</ref>
<ref id="ref86">
<label>86</label><mixed-citation publication-type="other" xlink:type="simple">Williams, P. M.: Sea surface chemistry: Organic carbon and organic and inorganic nitrogen and phosphorus in surface films and subsurface waters, Deep Sea Res., 14, 791–800, 1967.</mixed-citation>
</ref>
<ref id="ref87">
<label>87</label><mixed-citation publication-type="other" xlink:type="simple">Williams, P. M., Carlucci, A. F., Henrichs, S. M., van Vleet, E. S., Horrigan, S. G., Reid, F. M. H., and Robertson, K. J.: Chemical and microbiological studies of sea-surface films in the Southern Gulf of California and off the West Coast of Baja California, Mar. Chem., 19, 17–98, 1986.</mixed-citation>
</ref>
<ref id="ref88">
<label>88</label><mixed-citation publication-type="other" xlink:type="simple">Wozniak, A. S., Bauer, J. E., Sleighter, R. L., Dickhut, R. M., and Hatcher, P. G.: Technical Note: Molecular characterization of aerosol-derived water soluble organic carbon using ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry, Atmos. Chem. Phys., 8, 5099–5111, &lt;a href=&quot;http://dx.doi.org/10.5194/acp-8-5099-2008&quot;&gt;https://doi.org/10.5194/acp-8-5099-2008&lt;/a&gt;, 2008.</mixed-citation>
</ref>
<ref id="ref89">
<label>89</label><mixed-citation publication-type="other" xlink:type="simple">Wozniak, A. S., Bauer, J. E., and Dickhut, R. M.: Fossil and contemporary aerosol particulate organic carbon in the eastern United States: Implications for deposition and inputs to watersheds, Global Biogeochem. Cy., 25, GB2013, &lt;a href=&quot;http://dx.doi.org/10.1029/2010GB003855&quot;&gt;https://doi.org/10.1029/2010GB003855&lt;/a&gt;, 2011.</mixed-citation>
</ref>
<ref id="ref90">
<label>90</label><mixed-citation publication-type="other" xlink:type="simple">Wozniak, A. S., Bauer, J. E., and Dickhut, R. M.: Characteristics of water-soluble organic carbon associated with aerosol particles in the eastern United States, Atmos. Environ., 46, 181–188, 2012.</mixed-citation>
</ref>
<ref id="ref91">
<label>91</label><mixed-citation publication-type="other" xlink:type="simple">Wozniak, A. S., Shelley, R. U., Sleighter, R. L., Abdulla, H. A., Morton, P. L., Landing, W. M., and Hatcher, P. G.: Relationships among aerosol water soluble organic matter, iron and aluminum in European, North African, and Marine air masses from the 2010 US GEOTRACES cruise, Mar. Chem., 154, 24–33, 2013.</mixed-citation>
</ref>
<ref id="ref92">
<label>92</label><mixed-citation publication-type="other" xlink:type="simple">Zamora, L. M., Prospero, J. M., Hansell, D. A., and Trapp, J. M: Atmospheric P deposition to the subtropical North Atlantic: sources, properties, and relationship to N deposition, J. Geophys. Res.-Atmos., 118, 1546–1562, 2013.</mixed-citation>
</ref>
</ref-list>
</back>
</article>