Characteristics of atmospheric single particles during haze periods in a typical urban area of Beijing: A case study in October, 2014

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• 作者：Lang Liu¹ ; ^{liulang1991@foxmail.com" class="auth_mail" title="E-mail the corresponding author} ; Yanli Wang¹ ; Shiyong Du² ; Wenjie Zhang¹ ; Lujian Hou² ; Sverre Vedal¹ ; ³ ; Bin Han¹ ; Wen Yang¹ ; Mindong Chen⁴ ; Zhipeng Bai¹ ; ^{baizp@craes.org.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Single particle mass spectrometry ; Haze pollution ; Mixing state
• 刊名：Journal of Environmental Sciences
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：40
• 期：Complete
• 页码：145-153
• 全文大小：1168 K

文摘

To investigate the composition and possible sources of particles, especially during heavy haze pollution, a single particle aerosol mass spectrometer (SPAMS) was deployed to measure the changes of single particle species and sizes during October of 2014, in Beijing. A total of 2,871,431 particles with both positive and negative spectra were collected and characterized in combination with the adaptive resonance theory neural network algorithm (ART-2a). Eight types of particles were classified: dust particles (dust, 8.1%), elemental carbon (EC, 29.0%), organic carbon (OC, 18.0%), EC and OC combined particles (ECOC, 9.5%), Na-K containing particles (NaK, 7.9%), K-containing particles (K, 21.8%), organic nitrogen and potassium containing particles (KCN, 2.3%), and metal-containing particles (metal, 3.6%). Three haze pollution events (P1, P2, P3) and one clean period (clean) were analyzed, based on the mass and number concentration of PM_2.5 and the back trajectory results from the hybrid single particle Lagrangian integrated trajectory model (Hysplit-4 model). Results showed that EC, OC and K were the major components of single particles during the three haze pollution periods, which showed clearly increased ratios compared with those in the clean period. Results from the mixing state of secondary species of different types of particles showed that sulfate and nitrate were more readily mixed with carbon-containing particles during haze pollution episodes than in clean periods.