Special Session on Better Air Quality in Asia (II)

Bo Huang1,4, Ting Gan2, Chenglei Pei6, Mei Li This email address is being protected from spambots. You need JavaScript enabled to view it.1,3, Peng Cheng1,3, Duohong Chen5, Ridong Cai5, Yujun Wang6, Lei Li1,3, Zhengxu Huang1,3, Wei Gao1,3, Zhong Fu4, Zhen Zhou1,3

Institute of Mass Spectrometer and Atmospheric Environment, Jinan University, Guangzhou 510632, China
Sun Yat-sen University, Guangzhou 510275, China
Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou 510632, China
Guangzhou Hexin Instrument Co., Ltd., Guangzhou 510530, China
Guangdong Environmental Monitoring Center, Guangzhou 510308, China
6 Guangzhou Environmental Monitoring Center, Guangzhou 510060, China


Received: November 13, 2019
Revised: April 1, 2020
Accepted: May 17, 2020

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.4209/aaqr.2019.11.0582  

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Cite this article:

Huang, B., Gan, T., Pei, C., Li, M., Cheng, P., Chen, D., Cai, R., Wang, Y., Li, L., Huang, Z., Gao, W., Fu, Z. and Zhou, Z. (2020). Size-segregated Characteristics and Formation Mechanisms of Water-soluble Inorganic Ions during Different Seasons in Heshan of Guangdong, China. Aerosol Air Qual. Res. 20: 1961–1973. https://doi.org/10.4209/aaqr.2019.11.0582


  • Increased NOR and decreased SOR were observed during pollution days.
  • The highest SOR and NOR values were found in size ranges of 0.56–1 µm.
  • NO3 in Heshan showed different formation pathways in winter and summer.
  • Size-depended SO42– formation pathways were observed.
  • Aqueous reactions accelerated by NO2 might be a possible pathway of SO42–.


To identify the characteristics, sources, and formation mechanisms of aerosol particles during pollution episodes in the Pearl River Delta, 24 sets of size-segregated samples were collected in Heshan during July 2014 and January 2015 using a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI), and nine ions, viz., Na+, NH4+, K+, Mg2+, Ca2+, Cl, NO2, NO3, and SO42–, were investigated. The Na+, Mg2+, and Ca2+ were mainly distributed in the coarse particles, and were mainly from soil, dust, and sea salt. The fine-mode K+ during winter was mostly generated by biomass burning. The coarse-mode Cl originated from sea salt, whereas the fine-mode Cl resulted from the conversion of NH4Cl to the particle phase. Both the SO42– and the NO3 exhibited unimodal distributions during winter but bimodal ones during summer. The coarse-mode SO42– and NO3 arose from sea salt and heterogeneous reactions, respectively. An increase in the nitrogen oxidation ratio (NOR) and a decrease in the sulfur oxidation ratio (SOR) were observed on polluted days, with the highest values occurring in the 0.56–1 µm particle size fraction. The formation of NO3 was chiefly related toµ homogeneous gas-phase reactions during winter and nocturnal heterogeneous reactions involving N2O5 during summer, whereas the formation of SO42– was driven by gas-phase oxidation in the 0.056–0.32 µm size range and aqueous oxidation in the 0.56–3.2 µm range. Additionally, the SOR and the NO2 concentration displayed a positive correlation in the 0.056–1.8 µm particle size fraction, indicating that the potential formation of SO42– via aqueous reactions was accelerated by NO2.

Keywords: Water-soluble inorganic ions; Size distribution; Secondary formation; SOR; NOR.

Aerosol Air Qual. Res. 20 :1961 -1973 . https://doi.org/10.4209/aaqr.2019.11.0582  

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