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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>
</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-11-7893-2011</article-id>
<title-group>
<article-title>Carbonaceous species in PM&lt;sub&gt;2.5&lt;/sub&gt; at a pair of rural/urban sites in Beijing, 2005–2008</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Yang</surname>
<given-names>F.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Huang</surname>
<given-names>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>Duan</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>Zhang</surname>
<given-names>W.</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>He</surname>
<given-names>K.</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>Ma</surname>
<given-names>Y.</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>Brook</surname>
<given-names>J. R.</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>Tan</surname>
<given-names>J.</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>Zhao</surname>
<given-names>Q.</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>Cheng</surname>
<given-names>Y.</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Key Laboratory of Computational Geodynamics, College of Earth Science, Graduate University of Chinese Academy of Sciences, Beijing 100049, China</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Atmospheric Science and Technology Directorate/Science and Technology Branch, Environment Canada, Toronto, ON  M3H 5T4, Canada</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>School of Environment, Tsinghua University, Beijing 100084, China</addr-line>
</aff>
<pub-date pub-type="epub">
<day>04</day>
<month>08</month>
<year>2011</year>
</pub-date>
<volume>11</volume>
<issue>15</issue>
<fpage>7893</fpage>
<lpage>7903</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/11/7893/2011/acp-11-7893-2011.html">This article is available from http://www.atmos-chem-phys.net/11/7893/2011/acp-11-7893-2011.html</self-uri>
<self-uri xlink:href="http://www.atmos-chem-phys.net/11/7893/2011/acp-11-7893-2011.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/7893/2011/acp-11-7893-2011.pdf</self-uri>
<abstract>
<p>One-week integrated PM&lt;sub&gt;2.5&lt;/sub&gt; samples were collected over four years
(2005–2008) at a pair of sites, one rural and one urban site, in the area of
Beijing, China. Weekly organic and elemental carbon (OC and EC)
concentrations from these samples were measured to investigate their
atmospheric concentrations, temporal variation patterns and the factors
influencing these aspects. A slightly systematic decrease in annual mean
concentration of OC and an opposite trend for EC at both sites was observed.
Since OC accounted for about 70 % of total carbon (TC, i.e. OC + EC) the
total carbonaceous mass experienced a slight decline on a yearly basis over
the study period. Its fraction of PM&lt;sub&gt;2.5&lt;/sub&gt; mass at the urban site in 2008
was significantly lower than observed 10 years earlier (1999), indicating
that the relative importance of carbonaceous species in PM&lt;sub&gt;2.5&lt;/sub&gt; has
decreased. In urban Beijing clear seasonal variations (by factors of
1.35 ~ 3.0) were shown in both OC and EC with higher weekly
concentrations and fluctuations in winter and much lower values in summer
and spring. The minimum seasonal urban excesses of OC (3.0 μg m&lt;sup&gt;&amp;minus;3&lt;/sup&gt;)
and EC (1.3 μg m&lt;sup&gt;&amp;minus;3&lt;/sup&gt;) occurred in the summer of 2008, which were
only one-ninth and one-seventh of their corresponding maximum values,
respectively. This reduction in the urban-difference, coupled with more
positive stable carbon isotope values of EC at the urban site in that summer
relative to the preceding summers, supports that the special clean air
campaign for the 2008 Summer Olympic Games very likely had noticeable impact
on the ambient concentrations of carbonaceous aerosols in the Beijing area,
particularly on the local urban scale. Less consistent seasonal patterns in
OC and EC, their scattered correlation, and higher mass ratios of OC to EC
(OC/EC) at the rural site indicate more complex and variable major sources
regarding aerosol formation in the rural area. These emission sources
include biomass burning during the harvest seasons, widely used
high-polluting family stoves and small boilers for cooking and heating with
high OC/EC ratios, and a greater relative quantity of secondary organic
aerosols.</p>
</abstract>
<counts><page-count count="11"/></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"> Andreae, M. O. and Gelencsér, A.: Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols, Atmos. Chem. Phys., 6, 3131–3148, http://dx.doi.org/10.5194/acp-6-3131-2006doi:10.5194/acp-6-3131-2006, 2006. </mixed-citation>
</ref>
<ref id="ref2">
<label>2</label><mixed-citation publication-type="other" xlink:type="simple"> Beijing Municipal Bureau of Statistics: Beijing statistical Yearbook, available at: http://www.bjstats.gov.cn/tjnj/2008-tjnj (last access: February~2011), 2008 (in Chinese). </mixed-citation>
</ref>
<ref id="ref3">
<label>3</label><mixed-citation publication-type="other" xlink:type="simple"> Cao, J., Lee, S. C., Ho, K. F., Zou, S. C., Fung, K., Fung, K., Li, Y., Watson, J. G., and Chow, J. C.,: Spatial and seasonal variations of atmospheric organic carbon and elemental carbon in Pearl River Delta Region, China, Atmos. Environ., 38, 4447–4456, 2004. </mixed-citation>
</ref>
<ref id="ref4">
<label>4</label><mixed-citation publication-type="other" xlink:type="simple"> Cao, J. J., Lee, S. C., Chow, J. C., Watson , J. G., Ho, K. F., Zhang, R. J., Jin, Z. D., Shen, Z. X., Chen, G. C., Kang, Y. M., Zou, S. C., Zhang, L. Z., Qi, S. H., Dai, M. H., Cheng, Y., and Hu, K.: Spatial and seasonal distributions of carbonaceous aerosols over China, J. Geophys. Res., 112, D22S11, http://dx.doi.org/10.1029/2006JD008205doi:10.1029/2006JD008205, 2007. </mixed-citation>
</ref>
<ref id="ref5">
<label>5</label><mixed-citation publication-type="other" xlink:type="simple"> Cao,~J.-J., Chow,~J C., Tao,~J., Lee,~S.-C., Watson,~J G., Ho,~K.-f., Wang,~G.-H., Zhu,~C.-S., and Han,~Y.-M.: Stable carbon isotopes in aerosols from Chinese cities: Influence of fossil fuels, Atmos. Environ., 45, 1359–1363, 2011. </mixed-citation>
</ref>
<ref id="ref6">
<label>6</label><mixed-citation publication-type="other" xlink:type="simple"> Cermak, J. and Knutti, R.: Beijing Olympics as an aerosol field experiment, Geophys. Res. Lett., 36, L10806, http://dx.doi.org/10.1029/2009GL038572doi:10.1029/2009GL038572, 2009. </mixed-citation>
</ref>
<ref id="ref7">
<label>7</label><mixed-citation publication-type="other" xlink:type="simple"> Chan., C. K. and Yao, X. H.: Air pollution in mega cities in China, Atmos. Environ., 42, 1–42, 2008. </mixed-citation>
</ref>
<ref id="ref8">
<label>8</label><mixed-citation publication-type="other" xlink:type="simple"> Chan, T. W., Huang, L., Leaitch, W. R., Sharma, S., Brook, J. R., Slowik, J. G., Abbatt, J. P. D., Brickell, P. C., Liggio, J., Li, S.-M., and Moosmüller, H.: Observations of OM/OC and specific attenuation coefficients (SAC) in ambient fine PM at a rural site in central Ontario, Canada, Atmos. Chem. Phys., 10, 2393–2411, http://dx.doi.org/10.5194/acp-10-2393-2010doi:10.5194/acp-10-2393-2010, 2010.  </mixed-citation>
</ref>
<ref id="ref9">
<label>9</label><mixed-citation publication-type="other" xlink:type="simple"> Chen, Z., Ge, S., and Zhang, J.: Measurement and analysis for atmospheric aerosol particulates in Beijing, Res. Environ. Sci., 7(3), 1–9, 1994 (in Chinese). </mixed-citation>
</ref>
<ref id="ref10">
<label>10</label><mixed-citation publication-type="other" xlink:type="simple"> Cheng, Y., He, K. B., Duan, F. K., Zheng, M., Ma, Y. L., and Tan, J. H.: Measurement of semivolatile carbonaceous aerosols and its implications: A review, Environ. Int., 35, 674–681, 2009. </mixed-citation>
</ref>
<ref id="ref11">
<label>11</label><mixed-citation publication-type="other" xlink:type="simple"> Chow, J. C., Watson, J. G., Crow, D., Lowenthal, D. H., and Merrifield, T.: Comparison of IMPROVE and NIOSH carbon measurements, Aerosol Sci. Technol. 34, 23–34 , 2001. </mixed-citation>
</ref>
<ref id="ref12">
<label>12</label><mixed-citation publication-type="other" xlink:type="simple"> Duan, F., Liu, X., Yu, T., and Cachier, H.: Identification and estimate of biomass burning contribution to the urban aerosol organic carbon concentrations in Beijing, Atmos. Environ., 38, 1275–1282, 2004. </mixed-citation>
</ref>
<ref id="ref13">
<label>13</label><mixed-citation publication-type="other" xlink:type="simple"> Fenger, J.: Air pollution in the last 50 years – From local to global, Atmos. Environ., 43, 13–22, 2009. </mixed-citation>
</ref>
<ref id="ref14">
<label>14</label><mixed-citation publication-type="other" xlink:type="simple"> Flanner, M. G., Zender, C. S., Hess, P. G., Mahowald, N. M., Painter, T. H., Ramanathan, V., and Rasch, P. J.: Springtime warming and reduced snow cover from carbonaceous particles, Atmos. Chem. Phys., 9, 2481–2497, http://dx.doi.org/10.5194/acp-9-2481-2009doi:10.5194/acp-9-2481-2009, 2009. </mixed-citation>
</ref>
<ref id="ref15">
<label>15</label><mixed-citation publication-type="other" xlink:type="simple"> Gelencsér, A.: Carbonaceous Aerosol, Dordrecht, The Netherlands: Springer, 2004. </mixed-citation>
</ref>
<ref id="ref16">
<label>16</label><mixed-citation publication-type="other" xlink:type="simple"> Gray, H. A., Cass, G. R., Huntzicker, J. J., Heyerdahl, E. K., and Rau., J. A.: Characteristics of atmospheric organic and elemental carbon particle concentrations in Los Angeles, Environ. Sci. Technol., 20, 580–582, 1986. </mixed-citation>
</ref>
<ref id="ref17">
<label>17</label><mixed-citation publication-type="other" xlink:type="simple"> Hammes, K., Schmidt, M. W. I., Smernik, R. J., Currie, L. A. R., Ball, W. P., Nguyen, T. H., Louchouarn, P., Houel, S., Gustafsson, Ö., Elmquist, M., Cornelissen, G., Skjemstad, J. O., Masiello, C. A., Song, J., Peng, P., Mitra, S., Dunn, J. C., Hatcher, P. G., Hockaday, W. C., Smith, D. M., Hartkopf-Fröder, C., Böhmer, A., Lüer, B., Huebert, B. J., Amelung, W., Brodowski, S., Huang, L., Zhang, W., Gschwend, P. M., Flores-Cervantes, D. X., Largeau, C., Rouzaud, J.-N., Rumpel, C., Guggenberger, G., Kaiser, K., Rodionov, A., Gonzalez-Vila, F. J., Gonzalez-Perez, J. A., de la Rosa, J. M., Manning, D. A. C., López-Capél, E., and Ding, L.: Comparison of black carbon quantification methods using reference materials from soil, water, sediment and the atmosphere, and implications for the global carbon cycle, Global Biogeochem. Cy., 21, GB3016, http://dx.doi.org/10.1029/2006GB002914doi:10.1029/2006GB002914, 2007. </mixed-citation>
</ref>
<ref id="ref18">
<label>18</label><mixed-citation publication-type="other" xlink:type="simple"> Han, Z., Zhang R., Wang Q., Wang W., Cao J., and Xu, J.: Regional modeling of organic aerosols over China in summertime, J. Geophys. Res., 113, D11202, http://dx.doi.org/10.1029/2007JD009436doi:10.1029/2007JD009436, 2008. </mixed-citation>
</ref>
<ref id="ref19">
<label>19</label><mixed-citation publication-type="other" xlink:type="simple"> He, K., Yang, F., Ma, Y., Zhang, Q., Yao, X., Chan, C. K., Cadle, S., Chan, T., and Mulawa, P.: The characteristics of PM$_2.5$ in Beijing, China, Atmos. Environ., 35, 4959–4970, 2001. </mixed-citation>
</ref>
<ref id="ref20">
<label>20</label><mixed-citation publication-type="other" xlink:type="simple"> Huang, L., Brook, J. R., Zhang, W., Li, S. M., Graham, L., Ernst, D., Chivulescu, A., and Lu, G.: Stable isotope measurements of carbon fractions (OC/EC) in airborne particulate: A new dimension for source Characterization &amp; apportionment, Atmos. Environ., 40, 2690–2705, 2006. </mixed-citation>
</ref>
<ref id="ref21">
<label>21</label><mixed-citation publication-type="other" xlink:type="simple"> Huang, L., Lee, Y.-S., Chivulescu, A., Zhang, W., Ernst, D., Sharma, S., Worthy, D., Ernst, M., Brook, J., Leaitch, R., Chan, E., Tans, P., Sweeney, C., White, J., Vaughn, B., Yang, F., and He, K.: $^13$C/$^12$C isotopic constraints on inter-continental transport of fossil fuel CO&lt;sub&gt;2&lt;/sub&gt; &amp; BC aerosols, NOAA ESRL Global Monitoring Annual Conference, 17–19~May, Boulder, Colorado, USA, available at: http://www.esrl.noaa.gov/gmd/annualconference/previous/2010/pdfs/6-LinHuang.pdf (last access: May 2011), 2010. </mixed-citation>
</ref>
<ref id="ref22">
<label>22</label><mixed-citation publication-type="other" xlink:type="simple"> Ho, K. F., Lee, S. C., Cao, J. J., Chow, Judith C., Watson, John G., and Chan, C. K.: Seasonal variations and mass closure analysis of particulate matter in Hong Kong, Sci. Total Environ., 355, 276–287, 2006. </mixed-citation>
</ref>
<ref id="ref23">
<label>23</label><mixed-citation publication-type="other" xlink:type="simple"> IPCC: Climate Change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press, 160–168, 2007. </mixed-citation>
</ref>
<ref id="ref24">
<label>24</label><mixed-citation publication-type="other" xlink:type="simple"> Jacobson, M. Z.: Control of fossil-fuel particulate black carbon and organic matter, possibly the most effective method of slowing global warming, J. Geophys. Res., 107(D19), 4410, http://dx.doi.org/10.1029/2001JD001376doi:10.1029/2001JD001376, 2002. </mixed-citation>
</ref>
<ref id="ref25">
<label>25</label><mixed-citation publication-type="other" xlink:type="simple"> Jia, Y. T., Rahn, K. A., He, K. B., Wen, T. X., and Wang, Y. S.: A novel technique for quantifying the regional component of urban aerosol solely from its sawtooth cycles, J. Geophys. Res., 113, D21309, http://dx.doi:10.1029/2008JD010389doi:10.1029/2008JD010389, 2008. </mixed-citation>
</ref>
<ref id="ref26">
<label>26</label><mixed-citation publication-type="other" xlink:type="simple"> Kim, B. M., Teffera, S., and Zeldin, M. D.: Characterization of PM$_2.5$ and PM$_10$ in the South Coast Air Basin of Southern California: part 1-Spatial variations, J. Air Waste Manage., 50, 2034–2044, 2000. </mixed-citation>
</ref>
<ref id="ref27">
<label>27</label><mixed-citation publication-type="other" xlink:type="simple"> Kong, Q., Wu, Y., Yang, L., Du, H., Zhou, Y., and Fu, L.: Characteristics and intake dose of gaseous pollutants near a major Beijing road during the 29th Olympic Games, Acta Sci. Circumst., 30(2), 281–286, 2010 (in Chinese). </mixed-citation>
</ref>
<ref id="ref28">
<label>28</label><mixed-citation publication-type="other" xlink:type="simple"> Lee, H. S. and Kang, B.-W.: Chemical characteristics of principal PM$_2.5$ species in Chongju, South Korea, Atmos. Environ., 35, 739–746, 2001. </mixed-citation>
</ref>
<ref id="ref29">
<label>29</label><mixed-citation publication-type="other" xlink:type="simple"> Lei, Y., Zhang, Q., He, K. B., and Streets, D. G.: Primary anthropogenic aerosol emission trends for China, 1990-2005, Atmos. Chem. Phys., 11, 931–954, http://dx.doi.org/10.5194/acp-11-931-2011doi:10.5194/acp-11-931-2011, 2011. </mixed-citation>
</ref>
<ref id="ref30">
<label>30</label><mixed-citation publication-type="other" xlink:type="simple"> Li, X. H., Wang, S. X., Duan, L., Hao, J. M., and Nie, Y.: Carbonaceous aerosol emissions from household biofuel combustion in China, Environ. Sci. Technol., 43, 6076–6081, 2009. </mixed-citation>
</ref>
<ref id="ref31">
<label>31</label><mixed-citation publication-type="other" xlink:type="simple"> Liao, H., Henze, D. K., Seinfeld, J. H., Wu, S., and Mickley, L. J.: Biogenic secondary organic aerosol over the United States: Comparison of climatological simulations with observations, J. Geophys. Res., 112, D06201, http://dx.doi.org/10.1029/2006JD007813doi:10.1029/2006JD007813, 2007. </mixed-citation>
</ref>
<ref id="ref32">
<label>32</label><mixed-citation publication-type="other" xlink:type="simple"> McDow, S. R. and Huntzicker, J. J.: Vapor adsorption artefact in the sampling of organic aerosol: face velocity effects, Atmos. Environ., 24A, 2563–2571, 1990. </mixed-citation>
</ref>
<ref id="ref33">
<label>33</label><mixed-citation publication-type="other" xlink:type="simple"> Ramanathan, V. and Carmichael, G.: Global and regional climate changes due to black carbon, Nat. Geosci., 221–227, 2008. </mixed-citation>
</ref>
<ref id="ref34">
<label>34</label><mixed-citation publication-type="other" xlink:type="simple"> Singer, B. C., Kirchstetter, T. W., Harley, R. A., Kendall, G. R., and Hesson, J. M.: A fuel-based approach to estimating motor vehicle cold-start emissions, J. Air Waste Manage., 49, 125–135, 1999. </mixed-citation>
</ref>
<ref id="ref35">
<label>35</label><mixed-citation publication-type="other" xlink:type="simple"> Streets, D. G., Fu, J. S., Jang, C. J., Hao, J., He, K., Tang, X., Zhang, Y., Wang, Z., Zhang, Q., Wang, L., Wang, B., and Yu, C.: Air quality during the 2008 Beijing Olympic Games, Atmos. Environ., 41, 480–492, 2007. </mixed-citation>
</ref>
<ref id="ref36">
<label>36</label><mixed-citation publication-type="other" xlink:type="simple"> Turpin, B. J., Huntzicker, J. J., and Hering, S. V.: Investigation of organic aerosol sampling artefacts in the Los Angeles basin, Atmos. Environ., 28, 3061–3071, 1994. </mixed-citation>
</ref>
<ref id="ref37">
<label>37</label><mixed-citation publication-type="other" xlink:type="simple"> Turpin, B. J., Saxena, P. ,and Andrews, E.: Measuring and simulating particulate organics in the atmosphere: problems and prospects, Atmos. Environ., 34, 2983–3013, 2000. </mixed-citation>
</ref>
<ref id="ref38">
<label>38</label><mixed-citation publication-type="other" xlink:type="simple"> UNEP, United Nations Environmental Programme: Independent Environmental Assessment Beijing 2008 Plympic Games, Nairobi, Kenya, 2009, available at: http://www.unep.org/ pdf/BEIJING_REPORT_COMPLETE.pdf, (last access: February 2011), 2009. </mixed-citation>
</ref>
<ref id="ref39">
<label>39</label><mixed-citation publication-type="other" xlink:type="simple"> Wang, Y., Hao, J., McElroy, M. B., Munger, J. W., Ma, H., Chen, D., and Nielsen, C. P.: Ozone air quality during the 2008 Beijing Olympics: effectiveness of emission restrictions, Atmos. Chem. Phys., 9, 5237–5251, http://dx.doi.org/10.5194/acp-9-5237-2009doi:10.5194/acp-9-5237-2009, 2009. </mixed-citation>
</ref>
<ref id="ref40">
<label>40</label><mixed-citation publication-type="other" xlink:type="simple"> Wang, S. X., Zhao, M., Xing, J.,Wu, Y., Zhou, Y., Lei, Y., He, K. B., Fu, L. X., and Hao, J. M.: Quantifying the Air Pollutants Emission Reduction during the 2008 Olympic Games in Beijing, Environ. Sci. Technol., 44(7), 2490–2496, 2010a. </mixed-citation>
</ref>
<ref id="ref41">
<label>41</label><mixed-citation publication-type="other" xlink:type="simple"> Wang, T., Nie, W., Gao, J., Xue, L. K., Gao, X. M., Wang, X. F., Qiu, J., Poon, C. N., Meinardi, S., Blake, D., Wang, S. L., Ding, A. J., Chai, F. H., Zhang, Q. Z., and Wang, W. X.: Air quality during the 2008 Beijing Olympics: secondary pollutants and regional impact, Atmos. Chem. Phys., 10, 7603–7615, http://dx.doi.org/10.5194/acp-10-7603-2010doi:10.5194/acp-10-7603-2010, 2010b. </mixed-citation>
</ref>
<ref id="ref42">
<label>42</label><mixed-citation publication-type="other" xlink:type="simple"> Yang, F., He, K., Ma, Y., Zhang, Q., Cadle, S., Chan, T., and Mulawa, P.: Characterization of mass balance of PM$_2.5$ chemical speciation in Beijing, Environ. Chem., 23(3), 326–333, 2004 (in Chinese). </mixed-citation>
</ref>
<ref id="ref43">
<label>43</label><mixed-citation publication-type="other" xlink:type="simple"> Yang, F., He, K., Ye, B., Chen, X., Cha, L., Cadle, S. H., Chan, T., and Mulawa, P. A.: One-year record of organic and elemental carbon in fine particles in downtown Beijing and Shanghai, Atmos. Chem. Phys., 5, 1449–1457, http://dx.doi.org/10.5194/acp-5-1449-2005doi:10.5194/acp-5-1449-2005, 2005. </mixed-citation>
</ref>
<ref id="ref44">
<label>44</label><mixed-citation publication-type="other" xlink:type="simple"> Yang, F., Brook, J., He, K., Duan, F., and Ma, Y.: Temporal variability in fine carbonaceous aerosol over two years in two megacities: Beijing and Toronto, Adv. Atmos. Sci., 27(3), 705–714, http://dx.doi.org/10.1007/s00376-009-9103-6doi:10.1007/s00376-009-9103-6 , 2010. </mixed-citation>
</ref>
<ref id="ref45">
<label>45</label><mixed-citation publication-type="other" xlink:type="simple"> Yang, F., Tan, J., Zhao, Q., Du, Z., He, K., Ma, Y., Duan, F., Chen, G., and Zhao, Q.: Characteristics of PM$_2.5$ speciation in representative megacities and across China, Atmos. Chem. Phys., 11, 5207–5219, http://dx.doi.org/10.5194/acp-11-5207-2011doi:10.5194/acp-11-5207-2011, 2011a. </mixed-citation>
</ref>
<ref id="ref46">
<label>46</label><mixed-citation publication-type="other" xlink:type="simple"> Yang, F., Huang, L., Sharma, S., Brook, J. R., Zhang, W., Li, S.-M., and Tan, J.: Two-year observations of fine carbonaceous particles in variable sampling intervals, Atmos. Environ., 45, 2418–2426, 2011b. </mixed-citation>
</ref>
<ref id="ref47">
<label>47</label><mixed-citation publication-type="other" xlink:type="simple"> Ye, B. M., Ji, X. L., Yang, H. Z., Yao, X. H., Chan, C. K., Cadle, S. H., Chan, T., and Mulawa, P. A.: Concentration and chemical composition of PM$_2.5$ in Shanghai for a 1-year period, Atmos. Environ., 37(4), 499–510, 2003. </mixed-citation>
</ref>
<ref id="ref48">
<label>48</label><mixed-citation publication-type="other" xlink:type="simple"> Zhang, J., Smith, K. R., Ma, Y., Jiang, F., Qi, W., Liu, P., Kahlil, M. A. K., Rasmussen, R. A., and Thornelow, S. A.: Greenhouse gases and other airborne pollutants from household stoves in China: a database for emission factors, Atmos. Environ., 34: 4537–4549, 2000. </mixed-citation>
</ref>
<ref id="ref49">
<label>49</label><mixed-citation publication-type="other" xlink:type="simple"> Zhou, Y., Wu, Y., Yang, L., Fu, L., He, K., Wang, S., Hao, J., Chen, J., and Li, C.: The impact of transportation control measures on emission reductions during the 2008 Olympic Games in Beijing, China, Atmos. Environ., 44, 285–293, 2010. </mixed-citation>
</ref>
</ref-list>
</back>
</article>