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Environmental Science and Pollution Research

, Volume 26, Issue 3, pp 2649–2661 | Cite as

Characteristics and formation mechanisms of autumn haze pollution in Chengdu based on high time-resolved water-soluble ion analysis

  • Pan Wu
  • Xiaojuan Huang
  • Junke ZhangEmail author
  • Bin Luo
  • Jinqi Luo
  • Hongyi Song
  • Wei Zhang
  • Zhihan Rao
  • Yanpeng Feng
  • Jianqiang Zhang
Research Article
  • 90 Downloads

Abstract

To investigate the characteristics and formation mechanisms of haze pollution in the autumn season in the Sichuan Basin, hourly concentrations of water-soluble inorganic ions in PM2.5 (Na+, K +, NH4+, Mg2+, Ca2+, Cl, NO3, and SO42−) and major gaseous precursors (HCl, NH3, SO2, HONO, and HNO3) were measured by a gas and aerosol collector combined with ion chromatography (GAC-IC) from September to November 2017 at an urban site in Chengdu. The average mass concentration of total water-soluble ions was 36.9 ± 29.4 μg m−3, accounting for 62.8% of PM2.5 mass. Nitrate was the most abundant ion, comprising 41.2% of the total ions, followed by sulfate (27.1%) and ammonium (18.1%), indicating the important contribution of motor vehicle emissions to PM2.5 in Chengdu. Secondary formation of inorganic ions and biomass burning emissions played a vital role in the haze pollution processes. The formation of nitrate aerosol was particularly dominant and exhibited the most substantial increase during haze processes. It was likely to be produced primarily through homogeneous reactions, whereas heterogeneous reactions dominated sulfate formation. Additionally, distinct differences in diurnal patterns of secondary inorganic ions between clean days and polluted days were observed, reflecting different formation characteristics under polluted conditions. Due to a large increase of acidic aerosols, most particles collected on polluted days were acidic, and ammonium in most samples existed mainly as NH4HSO4 and NH4NO3. Furthermore, backward-trajectory cluster analysis revealed that air masses originating from the northeast of Chengdu prevailed in the autumn season, and haze pollution was dominated mainly by short-distance transport within the Sichuan Basin.

Keywords

PM2.5 Haze Water-soluble inorganic ions Gaseous precursors Chengdu 

Notes

Acknowledgements

The authors acknowledge the support from the Sichuan comprehensive monitoring station for environmental air quality.

Funding information

This work was financially supported by the key project of the Sichuan Science and Technology Program (2018SZ0288), the National Natural Science Foundation of China (41805095), and the Fundamental Research Funds for the Central Universities (2682017CX080).

Supplementary material

11356_2018_3630_MOESM1_ESM.docx (28 kb)
ESM 1 (DOCX 28 kb)

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Pan Wu
    • 1
  • Xiaojuan Huang
    • 2
  • Junke Zhang
    • 1
    Email author
  • Bin Luo
    • 3
  • Jinqi Luo
    • 1
  • Hongyi Song
    • 1
  • Wei Zhang
    • 3
  • Zhihan Rao
    • 3
  • Yanpeng Feng
    • 1
  • Jianqiang Zhang
    • 1
  1. 1.Faculty of Geosciences and Environmental EngineeringSouthwest Jiaotong UniversityChengduChina
  2. 2.Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, School of Atmospheric SciencesChengdu University of Information TechnologyChengduChina
  3. 3.Sichuan Environmental Monitoring CenterChengduChina

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