title: Characteristics of atmospheric single particles during haze periods in a typical urban area of Beijing: A case study in October, 2014.
abstract: 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 PM2.5 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.
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. E-mail: liulang1991@foxmail.com. Electronic address: liulang1991@foxmail.com.
authors.forename: Lang
authors.initials: L
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. E-mail: liulang1991@foxmail.com.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Environmental Protection Science Research Institute of Ji'nan, Ji'nan 250014, China.
authors.forename: Shiyong
authors.initials: S
authors.lastname: Du
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. E-mail: liulang1991@foxmail.com.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Environmental Protection Science Research Institute of Ji'nan, Ji'nan 250014, China.
authors.forename: Lujian
authors.initials: L
authors.lastname: Hou
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. E-mail: liulang1991@foxmail.com; Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA.
authors.forename: Sverre
authors.initials: S
authors.lastname: Vedal
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. E-mail: liulang1991@foxmail.com.
authors.forename: Bin
authors.initials: B
authors.lastname: Han
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. E-mail: liulang1991@foxmail.com.
authors.forename: Wen
authors.initials: W
authors.lastname: Yang
authors.affiliation: Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044, China.
authors.forename: Mindong
authors.initials: M
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. E-mail: liulang1991@foxmail.com. Electronic address: baizp@craes.org.cn.
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Bai
mesh_terms: D000336:Aerosols / Q000032:analysis / Q000737:chemistry; D000393:Air Pollutants / Q000032:analysis / Q000737:chemistry; D000397:Air Pollution / Q000032:analysis*; D000068476:Beijing; D002244:Carbon / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D013058:Mass Spectrometry; D008670:Metals / Q000032:analysis; D009584:Nitrogen / Q000032:analysis / Q000737:chemistry; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis* / Q000737:chemistry*; D011188:Potassium / Q000032:analysis / Q000737:chemistry; D012964:Sodium / Q000032:analysis / Q000737:chemistry
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D008670:Metals; D052638:Particulate Matter; D002244:Carbon; D012964:Sodium; D009584:Nitrogen; D011188:Potassium
keywords: Haze pollution; Mixing state; Single particle mass spectrometry