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Evolution of Key Chemical Components in PM2.5 and Potential Formation Mechanisms of Serious Haze Events in Handan, China

Category: Aerosol Source, Formation, Transport, Deposition, and its Chemical and Physical Processes

Volume: 18 | Issue: 7 | Pages: 1545-1557
DOI: 10.4209/aaqr.2017.10.0386

Export Citation:  RIS | BibTeX

Chengyu Zhang1, Litao Litao Wang 1, Mengyao Qi1, Xiao Ma1, Le Zhao1, Shangping Ji1, Yu Wang1, Xiaohan Lu1, Qing Wang1, Ruiguang Xu1, Yongliang Ma2

  • 1 Department of Environmental Engineering, College of Energy and Environmental Engineering, Hebei University of Engineering, Handan 056038, China
  • 2 School of Environment, Tsinghua University, Beijing 100084, China


Nitrate in PM2.5 decreased from the clean level to the heavily polluted level.
POA in PM2.5 increased with the aggravation of haze.
Liquid reactions of NO2 are enhanced in the pollution stage during the heating season.


Handan has been one of the most polluted cities in China since 2013 and became the top city for PM2.5 in 2017. In this research, we observed coarse particulate matter (PM10), fine particulate matter (PM2.5), submicron particulate matter (PM1), and the chemical composition of PM2.5 from November 16, 2015, till March 14, 2016, in Handan. During the observation period, hourly concentrations of PM10, PM2.5, and PM1 peaked at 1070.1, 864.4, and 519.5 µg m–3, respectively. Severe pollution occurred on a large fraction of days in the heating season, which was characterized by frequent and long-lasting pollution episodes. A large fraction of the transport trajectories during nine typical episodes during that period in Handan were from the northwest. Water-soluble ions (sulfate, nitrate, and ammonium) in PM2.5 accounted for the largest proportion at all pollution levels. The highest proportion of SIA occurred in a heavily polluted episode, during which it was as high as 50.0% (sulfate: 18.8%, nitrate: 18.7%, and ammonium: 12.5%). The sulfate and ammonium in PM2.5 increased gradually while the nitrate decreased as the level of pollution rose from clean to heavily polluted. The fraction of SOA and OM to PM2.5 decreased as the pollution level increased, indicating a weakening of photochemical reactions. The POA in PM2.5 increased with the aggravation of haze, and the heterogeneous chemistry was enhanced by the aggravation of pollution. Liquid reactions were important in the formation of sulfate during pollution and non-pollution stages. Liquid reactions of NO2 are enhanced in the pollution stage during the heating season in Handan.


Particulate matter Haze Heterogeneous chemistry Aerosol water content

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