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Particle Liquid Water Content and Aerosol Acidity Acting as Indicators of Aerosol Activation Changes into Cloud Condensation Nuclei (CCN) during Pollution Eruption in Guangzhou of South China

Category: Aerosol and Atmospheric Chemistry

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DOI: 10.4209/aaqr.2019.09.0476
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Junyan Duan1, Rui Lyu1, Yanyu Wang1, Xin Xie1, Yunfei Wu2, Jun Tao3, Tiantao Cheng 4,5, Yuehui Liu1, Yarong Peng1, Renjian Zhang 2, Qianshan He6, Wei Ga6, Xianming Zhang7, Qian Zhang7

  • 1 Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
  • 2 Key Laboratory of Region Climate-Environment Research for Temperate East Asia (TEA), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
  • 3 South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou 510655, China
  • 4 Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences, Fudan University, Shanghai 200438, China
  • 5 Shanghai Institute of Eco-Chongming (SIEC), Shanghai 200062, China
  • 6 Shanghai Meteorological Bureau, Shanghai 200030, China
  • 7 Wireless Product R&D Institute, ZTE Corporation, Shenzhen 518057, China


  • Aerosol pH and CCN increase rapidly with PM2.5 during pollution outbreak.
  • Aerosol CCN activity varies synchronously with water species and water content.
  • A possible approach to track aerosol activation changes during pollution eruption.


Atmospheric pollutions have been found to modify particle hygroscopicity and aerosol ability to become cloud condensation nuclei (CCN). Aerosols and bulk CCN were measured in urban Guangzhou during pollution periods in January 2016, and particle liquid water content (PLWC) and aerosol acidity (Aero-pH) were calculated to examine their possible effects on aerosol CCN activation. The results showed that PLWC and Aero-pH are likely to play key roles in enhancing aerosol activation in the early stages of pollution episodes. With analysis of calculated and observed data, CCN, PLWC, Aero-pH and water soluble inorganic matter (WSIM) are demonstrated to link closely with each other, particularly in nocturnal times, and Aero-pH and PLWC are found to act as pre-occurring indicators of activated aerosols and aerosol activity during pollution eruption, respectively. The feedback of chemical reactions, aerosol acidity and particle water content is in theory conducive to explain changes of aerosol activation accompanying with particle accumulating and aging. Our analysis provides some insights into the formation of explosive particle pollution characterized by secondary aerosols, and suggests a possible approach to track or characterize the effects of rapid pollution formation on aerosol activation changes into CCN without measurements of CCN and aerosol number.


Aerosol acidity Particle water content CCN Pollution

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