<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" dtd-version="3.0" xml:lang="en">
<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>
</journal-title-group>
<issn pub-type="epub">1680-7324</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/acp-6-4079-2006</article-id>
<title-group>
<article-title>Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Sihto</surname>
<given-names>S.-L.</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>Kulmala</surname>
<given-names>M.</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>Kerminen</surname>
<given-names>V.-M.</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>Dal Maso</surname>
<given-names>M.</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>Petäjä</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>Riipinen</surname>
<given-names>I.</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>Korhonen</surname>
<given-names>H.</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>Arnold</surname>
<given-names>F.</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>Janson</surname>
<given-names>R.</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>Boy</surname>
<given-names>M.</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>Laaksonen</surname>
<given-names>A.</given-names>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Lehtinen</surname>
<given-names>K. E. J.</given-names>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>University of Helsinki, Department of Physical Sciences, P.O. Box 64,  00014 University of Helsinki, Finland</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Finnish Meteorological Institute, Climate and Global Change, Erik  Palmenin Aukio 1, P.O. Box 503, 00101 Helsinki, Finland</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Atmospheric Physics Division, Max-Planck Institute for Nuclear  Physics (MPIK), P.O. Box 103980, 69029 Heidelberg, Germany</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>University of Stockholm, Department of Applied Environmental Science,  Air Pollution Laboratory, Frescativägen 54, 10691 Stockholm,  Sweden</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>University of Kuopio, Department of Applied Physics, P.O. Box 1627,  70211 Kuopio, Finland</addr-line>
</aff>
<aff id="aff6">
<label>6</label>
<addr-line>Finnish Meteorological Institute and University of Kuopio, Department  of Applied Physics, P.O. Box 1627, 70211 Kuopio, Finland</addr-line>
</aff>
<pub-date pub-type="epub">
<day>11</day>
<month>09</month>
<year>2006</year>
</pub-date>
<volume>6</volume>
<issue>12</issue>
<fpage>4079</fpage>
<lpage>4091</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>
<self-uri xlink:href="http://www.atmos-chem-phys.net/6/4079/2006/acp-6-4079-2006.html">This article is available from http://www.atmos-chem-phys.net/6/4079/2006/acp-6-4079-2006.html</self-uri>
<self-uri xlink:href="http://www.atmos-chem-phys.net/6/4079/2006/acp-6-4079-2006.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys.net/6/4079/2006/acp-6-4079-2006.pdf</self-uri>
<abstract>
<p>We have investigated the formation and early growth of atmospheric secondary
aerosol particles building on atmospheric measurements. The measurements were
part of the QUEST 2 campaign which took place in spring 2003 in
Hyytiälä (Finland). During the campaign numerous aerosol particle
formation events occurred of which 15 were accompanied by gaseous sulphuric
acid measurements. Our detailed analysis of these 15 events is focussed on
nucleation and early growth (to a diameter of 3 nm) of fresh particles. It
revealed that new particle formation seems to be a function of the gaseous
sulphuric acid concentration to the power from one to two when the time delay
between the sulphuric acid and particle number concentration is taken into
account. From the time delay the growth rates of freshly nucleated particles
from 1 nm to 3 nm were determined. The mean growth rate was 1.2 nm/h and it
was clearly correlated with the gaseous sulphuric acid concentration. We
tested two nucleation mechanisms &amp;ndash; recently proposed cluster activation and
kinetic type nucleation &amp;ndash; as possible candidates to explain the observed
dependences, and determined experimental nucleation coefficients. We found
that some events are dominated by the activation mechanism and some by the
kinetic mechanism. Inferred coefficients for the two nucleation mechanisms
are the same order of magnitude as chemical reaction coefficients in the gas
phase and they correlate with the product of gaseous sulphuric acid and
ammonia concentrations. This indicates that besides gaseous sulphuric acid
also ammonia has a role in nucleation.</p>
</abstract>
<counts><page-count count="13"/></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"> Bernd, T., Böge, O., Stratmann, F., Heintzenberg, J., and Kulmala, M.: Rapid formation of new sulfuric acid particles at near-atmospheric conditions, Science, 307(5710), 698&amp;ndash;700, 2005. </mixed-citation>
</ref>
<ref id="ref2">
<label>2</label><mixed-citation publication-type="other" xlink:type="simple"> Birmili, W. and Wiedensohler, A.: The influence of meteorological parameters on ultrafine particle production at a continental site, J. Aerosol Sci., 29, S1015&amp;ndash;1016, 1998. </mixed-citation>
</ref>
<ref id="ref3">
<label>3</label><mixed-citation publication-type="other" xlink:type="simple"> Birmili, W., Berresheim, H., Plass-Dülmer, C., Elste, T., Gilge, S., Wiedensohler, A., and Uhrner, U.: The Hohenpeissenberg aerosol formation experiment (HAFEX): a long-term study including size-resolved aerosol, H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;, OH, and monoterpenes measurements, Atmos. Chem. Phys., 3, 361&amp;ndash;376, 2003. </mixed-citation>
</ref>
<ref id="ref4">
<label>4</label><mixed-citation publication-type="other" xlink:type="simple"> Boy, M., Kulmala, M., Ruuskanen, T. M., Pihlatie, M., Reissell, A., Aalto, P. P., Keronen, P., Dal Maso, M., Hellen, H., Hakola, H., Jansson, R., Hanke, M., and Arnold, F.: Sulphuric acid closure and contribution to nucleation mode particle growth, Atmos. Chem. Phys., 5, 863&amp;ndash;878, 2005. </mixed-citation>
</ref>
<ref id="ref5">
<label>5</label><mixed-citation publication-type="other" xlink:type="simple"> Cabada, J. C., Khlystov, A., Wittig, A. E., Pilinis, C., and Pandis, S. N.: Light scattering by fine particles during the Pittsburgh Air Quality Study: Measurements and modelling, J. Geophys. Res., 109, D16S03, doi:10.1029/2003JD004155, 2004. </mixed-citation>
</ref>
<ref id="ref6">
<label>6</label><mixed-citation publication-type="other" xlink:type="simple"> Dal Maso, M., Kulmala, M., Riipinen, I., Wagner, R., Hussein, T., Aalto, P. P., and Lehtinen, K. E. J.: Formation and growth of fresh atmospheric aerosols: eight years of aerosol size distribution data from SMEAR II, Hyytiälä, Finland, Boreal Environ. Res., 10, 323&amp;ndash;336, 2005. </mixed-citation>
</ref>
<ref id="ref7">
<label>7</label><mixed-citation publication-type="other" xlink:type="simple"> Donaldson, K., Li, X. Y., and MacNee, W.: Ultra-fine (nanometre) particle mediated lung injury, J. Aerosol. Sci., 29, 553&amp;ndash;560, 1998. </mixed-citation>
</ref>
<ref id="ref8">
<label>8</label><mixed-citation publication-type="other" xlink:type="simple"> Dunn, M. J., Jimenez, J.-L., Baumgartner, D., Castro, T., McMurry, P. H., and Smith, J. N.: Measurements of Mexico City nanoparticle size distributions: Observations of new particle formation and growth, Geophys. Res. Lett., 31, L10102, doi:10.1029/2004GL019483, 2004. </mixed-citation>
</ref>
<ref id="ref9">
<label>9</label><mixed-citation publication-type="other" xlink:type="simple"> Fiedler, V., Dal Maso, M., Boy, M., Aufmhoff, H., Hoffmann, J., Schuch, T., Birmili, W., Hanke, M., Uecker, J., Arnold, F., and Kulmala, M.: The contribution of sulphuric acid to atmospheric particle formation and growth: a comparison between boundary layers in Northern and Central Europe, Atmos. Chem. Phys., 5, 1773&amp;ndash;1785, 2005. </mixed-citation>
</ref>
<ref id="ref10">
<label>10</label><mixed-citation publication-type="other" xlink:type="simple"> Hanke, M., Uecker, J., Reiner, T., and Arnold, F.: Atmospheric peroxy radicals: ROXMAS, a new mass-spectrometric methodology for speciated measurements of HO2 and Sigma RO2 and first results, Int. J. Mass Spectr., 213(2&amp;ndash;3), 91&amp;ndash;99, 2002. </mixed-citation>
</ref>
<ref id="ref11">
<label>11</label><mixed-citation publication-type="other" xlink:type="simple"> Hari, P. and Kulmala, M.: Station for Measuring Ecosystem&amp;ndash;Atmosphere Relations (SMEAR II), Boreal Environ. Res., 10, 315&amp;ndash;322, 2005. </mixed-citation>
</ref>
<ref id="ref12">
<label>12</label><mixed-citation publication-type="other" xlink:type="simple"> Janson, R., Rosman, K., Karlsson, A., and Hansson, H.-C.: Biogenic emissions and gaseous precursors to forest aerosols, Tellus 53B, 423&amp;ndash;440, 2001. </mixed-citation>
</ref>
<ref id="ref13">
<label>13</label><mixed-citation publication-type="other" xlink:type="simple"> Kerminen, V.-M. and Kulmala, M.: Analytical formulae connecting the &quot;real&quot; and the &quot;apparent&quot; nucleation rate and the nuclei number concentration for atmospheric nucleation events, J. Aerosol Sci., 33, 609&amp;ndash;622, 2002. </mixed-citation>
</ref>
<ref id="ref14">
<label>14</label><mixed-citation publication-type="other" xlink:type="simple"> Korhonen, H., Lehtinen, K. E. J., and Kulmala, M.: Multicomponent aerosol dynamics model UHMA: model development and validation, Atmos. Chem. Phys., 4, 757&amp;ndash;771, 2004. </mixed-citation>
</ref>
<ref id="ref15">
<label>15</label><mixed-citation publication-type="other" xlink:type="simple"> Korhonen, P., Kulmala, M., Laaksonen, A., Viisanen, Y., McGraw, R., and Seinfeld, J. H.: Ternary nucleation of H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;, NH&lt;sub&gt;3&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;O in the atmosphere, J. Geophys. Res., 104, 26 349&amp;ndash;26 353, 1999. </mixed-citation>
</ref>
<ref id="ref16">
<label>16</label><mixed-citation publication-type="other" xlink:type="simple"> Kulmala, M., Toivonen, A., Mäkelä, J. M., and Laaksonen, A.: Analysis of the growth of nucleation mode particles observed in Boreal forest, Tellus, 50B, 449&amp;ndash;462, 1998. </mixed-citation>
</ref>
<ref id="ref17">
<label>17</label><mixed-citation publication-type="other" xlink:type="simple"> Kulmala, M., Hämeri, K., Aalto, P. P., Mäkelä, J. M., Pirjola, L., Nilsson, E. D., Buzorius, G., Rannik, Ü, Dal Maso, M., Seidl, W., Hoffmann, T., Janson, R., Hansson, H.-C., Viisanen, Y., Laaksonen, A., and O&apos;Dowd, C. D.: Overview of the international project on Biogenic aerosol formation in the boreal forest (BIOFOR), Tellus 53B, 324&amp;ndash;343, 2001a. </mixed-citation>
</ref>
<ref id="ref18">
<label>18</label><mixed-citation publication-type="other" xlink:type="simple"> Kulmala, M., Dal Maso, M., Mäkelä, J. M., Pirjola, L., Väkevä, M., Aalto, P,. Miikkulainen, P., Hämeri, K., and O&apos;Dowd, C. D.: On the formation, growth and composition of nucleation mode particles, Tellus, 53B, 479&amp;ndash;490, 2001b. </mixed-citation>
</ref>
<ref id="ref19">
<label>19</label><mixed-citation publication-type="other" xlink:type="simple"> Kulmala, M.: How Particles Nucleate and Grow, Science, 302, 1000&amp;ndash;1001, 2003. </mixed-citation>
</ref>
<ref id="ref20">
<label>20</label><mixed-citation publication-type="other" xlink:type="simple"> Kulmala, M., Vehkamäki, H., Petäjä, T., Dal Maso, M., Lauri, A., Kerminen, V.-M., Birmili, W., and McMurry, P. H.: Formation and growth rates of ultrafine atmospheric particles: A review of observations, J. Aerosol Sci., 35, 143&amp;ndash;176, 2004a. </mixed-citation>
</ref>
<ref id="ref21">
<label>21</label><mixed-citation publication-type="other" xlink:type="simple"> Kulmala, M., Laakso, L., Lehtinen, K. E. J., Riipinen, I., Dal Maso, M., Anttila, T., Kerminen, V.-M., Horrak, U., Vana, M., and Tammet, H.: Initial steps of aerosol growth, Atmos. Chem. Phys., 4, 2553&amp;ndash;2560, 2004b. </mixed-citation>
</ref>
<ref id="ref22">
<label>22</label><mixed-citation publication-type="other" xlink:type="simple"> Kulmala, M., Lehtinen, K. E. J., Laakso, L., Mordas, G., and Hämeri, K.: On the existence of neutral atmospheric clusters, Boreal Environ. Res., 10, 79&amp;ndash;87, 2005a. </mixed-citation>
</ref>
<ref id="ref23">
<label>23</label><mixed-citation publication-type="other" xlink:type="simple"> Kulmala, M., Lehtinen, K. E. J., and Laaksonen, A.: Cluster activation theory as an explanation of the linear dependence between formation rate of 3 nm particles and sulphuric acid concentration, Atmos. Chem. Phys., 6, 787&amp;ndash;793, 2006. </mixed-citation>
</ref>
<ref id="ref24">
<label>24</label><mixed-citation publication-type="other" xlink:type="simple"> Laakso, L., Anttila, T., Lehtinen, K. E. J., Aalto, P. P., Kulmala, M., Hõrrak, U., Paatero, J., Hanke, M., and Arnold, F.: Kinetic nucleation and ions in boreal particle formation events, Atmos. Chem. Phys., 4, 2353&amp;ndash;2366, 2004a. </mixed-citation>
</ref>
<ref id="ref25">
<label>25</label><mixed-citation publication-type="other" xlink:type="simple"> Laakso, L., Petäjä, T., Lehtinen, K. E. J., Kulmala, M., Paatero, J., Hõrrak, U., Tammet, H., and Joutsensaari, J.: Ion production rate in a boreal forest based on ion, particle and radiation measurements, Atmos. Chem. Phys., 4, 1933&amp;ndash;1943, 2004b. </mixed-citation>
</ref>
<ref id="ref26">
<label>26</label><mixed-citation publication-type="other" xlink:type="simple"> Laaksonen, A., Hamed, A., Joutsensaari, J., Hiltunen, L., Cavalli, F., Junkermann, W., Asmi, A., Fuzzi, S., and Faccini, M. C.: Cloud condensation nucleus production from nucleation events at a highly polluted region, Geophys. Res. Lett., 32, L06812, doi:10.1029/2004GL022092, 2005. </mixed-citation>
</ref>
<ref id="ref27">
<label>27</label><mixed-citation publication-type="other" xlink:type="simple"> Lehtinen, K. E. J. and Kulmala, M.: A model for particle formation and growth in the atmosphere with molecular resolution in size, Atmos. Chem. Phys., 3, 251&amp;ndash;257, 2003. </mixed-citation>
</ref>
<ref id="ref28">
<label>28</label><mixed-citation publication-type="other" xlink:type="simple"> Lohmann, U. and Feichter, J.: Global indirect aerosol effects: a review, Atmos. Chem. Phys., 5, 715&amp;ndash;737, 2005. </mixed-citation>
</ref>
<ref id="ref29">
<label>29</label><mixed-citation publication-type="other" xlink:type="simple"> Lushnikov, A. A. and Kulmala, M.: Dimers in nucleating vapors, Phys. Rev. E, 58, 3157&amp;ndash;3167, 1998. </mixed-citation>
</ref>
<ref id="ref30">
<label>30</label><mixed-citation publication-type="other" xlink:type="simple"> McMurry, P. H. and Friedlander, S. K.: New particle formation in the presence of an aerosol, Atmos. Environ., 13, 1635&amp;ndash;1651, 1979. </mixed-citation>
</ref>
<ref id="ref31">
<label>31</label><mixed-citation publication-type="other" xlink:type="simple"> Mäkelä, J. M., Aalto, P., Jokinen, V., Pohja, T., Nissinen, A., Palmroth, S., Markkanen, T., Seitsonen, K., Lihavainen, H., and Kulmala, M.: Observations of ultrafine aerosol particle formation and growth in boreal forest, Geophys. Res. Lett., 24, 1219&amp;ndash;1222, 1997. </mixed-citation>
</ref>
<ref id="ref32">
<label>32</label><mixed-citation publication-type="other" xlink:type="simple"> Mönkkönen, P., Koponen, I. K., Lehtinen, K. E. J., Hämeri, K., Uma, R., and Kulmala, M.: Measurements in a highly polluted Asian mega city: Observations of aerosol aerosol number size distributions, modal parameters and nucleation events, Atmos. Chem. Phys., 5, 57&amp;ndash;66, 2005. </mixed-citation>
</ref>
<ref id="ref33">
<label>33</label><mixed-citation publication-type="other" xlink:type="simple"> O&apos;Dowd, C., McFiggans, G., Creasey, D. J., Pirjola, L., Hoell, C., Smith, M. H., Allan, B. J., Plane, J. M. C., Heard, D. E., Lee, J. D., Pilling, M. J., and Kulmala M.: On the photochemical production of new particles in the coastal boundary layer, Geophys. Res. Lett., 26, 1707&amp;ndash;1710, 1999. </mixed-citation>
</ref>
<ref id="ref34">
<label>34</label><mixed-citation publication-type="other" xlink:type="simple"> Ramanathan, V., Crutzen, P. J., Kiehl, J. T., and Rosenfeld, D.: Aerosol, climate, and the hydrological cycle, Science, 294, 2119&amp;ndash;2124, 2001. </mixed-citation>
</ref>
<ref id="ref35">
<label>35</label><mixed-citation publication-type="other" xlink:type="simple"> Sekiguchi, M., Nakajima, T., Suzuki, K., Kawamoto, K., Higurashi, A., Rosenfeld, D., Sano, I., and Mukai, S.: A study of the direct and indirect effects of aerosols using global satellite data sets of aerosol and cloud parameters, J. Geophys. Res., 108(D22), 4699, doi:10.1029/2002JD003359, 2003. </mixed-citation>
</ref>
<ref id="ref36">
<label>36</label><mixed-citation publication-type="other" xlink:type="simple"> Smith, J. N., Moore, K. F., Eisele, F. L., Voisin D., Ghimire, A. K., Sakurai H., and McMurry, P. H.: Chemical composition of atmospheric nanoparticles during nucleation events in Atlanta, J. Geophys. Res., 110, D22S03, doi:10.1029/2005JD005912, 2005.  </mixed-citation>
</ref>
<ref id="ref37">
<label>37</label><mixed-citation publication-type="other" xlink:type="simple"> Stanier, C. O., Khlystov, A. Y., and Pandis, S. N.: Nucleation events during the Pittsburg Air Quality Study: Description and relation to key meteorological, gas phase and aerosol parameters, Aerosol Sci. Technol., 38(S1), 253&amp;ndash;264, 2004. </mixed-citation>
</ref>
<ref id="ref38">
<label>38</label><mixed-citation publication-type="other" xlink:type="simple"> Stolzenburg, M. R., McMurry, P. H., Sakurai, H., Smith, J. N., Mauldin III, R. L., Eisele, F. L., and Clement, C. F.: Growth rates of freshly nucleated particles in Atlanta, J. Geophys. Res., 110, D22S05, doi:10.1029/2005JD005935, 2005. </mixed-citation>
</ref>
<ref id="ref39">
<label>39</label><mixed-citation publication-type="other" xlink:type="simple"> Stieb, D. M., Judek, S., and Burnett, R.T.: Meta-analysis of time-series studies of air pollution and mortality: Effects of gases and particles and their influence of cause of death, age and season, J. Air &amp; Manage. Assoc., 52, 470&amp;ndash;484, 2002. </mixed-citation>
</ref>
<ref id="ref40">
<label>40</label><mixed-citation publication-type="other" xlink:type="simple"> Vana, M., Kulmala, M., Dal Maso, M., Hõrrak, U., and Tamm, E.: Comparative study of nucleation mode aerosol particles and intermediate air ions formation events at three sites, J. Geophys. Res., 109, D17201, 2004. </mixed-citation>
</ref>
<ref id="ref41">
<label>41</label><mixed-citation publication-type="other" xlink:type="simple"> Vehkamäki, H., Dal Maso, M., Hussein, T., Flanagan, R., Hyvärinen, A., Lauros, J., Merikanto, J., Mönkkönen, P., Pihlatie, M., Salminen, K., Sogacheva, L., Thum, T., Ruuskanen, T., Keronen, P., Aalto, P., Hari, P., Lehtinen, K., and Kulmala, M.: Atmospheric particle formation events at Värriö measurement station in Finnish Lapland 1998&amp;ndash;2002, Atmos. Chem. Phys., 4, 2015&amp;ndash;2023, 2004. </mixed-citation>
</ref>
<ref id="ref42">
<label>42</label><mixed-citation publication-type="other" xlink:type="simple"> Väkevä, M., Hämeri, K., Puhakka, T., Nilsson, E. D., Hohti, H., and Mäkelä, J. M.: Effects of meteorological processes on aerosol particle size distribution in an urban background area, J. Geophys. Res., 105, 9807&amp;ndash;9821, 2000. </mixed-citation>
</ref>
<ref id="ref43">
<label>43</label><mixed-citation publication-type="other" xlink:type="simple"> Weber, R. J., McMurry, P. H., Eisele, F. L., and Tanner, D. J.: Measurement of expected nucleation precursor species and 3&amp;ndash;500 nm diameter particles at Mauna Loa Observatory, Hawaii, J. Atmos. Sci., 52, 2242&amp;ndash;2257, 1995. </mixed-citation>
</ref>
<ref id="ref44">
<label>44</label><mixed-citation publication-type="other" xlink:type="simple"> Weber, R. J., Marti, J. J., McMurry, P. H., Eisele, F. L., Tanner, D. J., and Jefferson, A.: Measurements of new particle formation and ultrafine particle growth rates at a clean continental site, J. Geophys. Res., 102, 4375&amp;ndash;4385, 1997. </mixed-citation>
</ref>
<ref id="ref45">
<label>45</label><mixed-citation publication-type="other" xlink:type="simple"> Wehner, B., Wiedensohler, A., Tuch, T. M., Wu, Z. J., Hu, M., Slanina, J., and Kiang, C. S.: Variability of the aerosol number size distribution in Beijing, China: New particle formation, dust storms, and high continental background, Geophys. Res. Lett., 31, L22108, doi:10.1029/2004GL021596, 2004. </mixed-citation>
</ref>
<ref id="ref46">
<label>46</label><mixed-citation publication-type="other" xlink:type="simple"> Zhang, Q., Stanier, C. O., Canagaratna, M. R., Jayne, J. T., Worsnop, D. R., Pandis, S. N., and Jimenez, J. L.: Insights into the chemistry of new particle formation and growth events in Pittsburg based on aerosol mass spectrometry, Environ. Sci. Technol., 38, 4797&amp;ndash;4809, 2004. </mixed-citation>
</ref>
</ref-list>
</back>
</article>