Size-resolved aerosol ionic composition and secondary formation at Mount Heng in South Central China

Xinfeng Wang, Wenxing Wang, Likun Xue, Xiaomei Gao, Wei Nie, Yangchun Yu, Yang Zhou, Lingxiao Yang, Qingzhu Zhang, Tao Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

5 Citations (Scopus)

Abstract

To understand the size-resolved aerosol ionic composition and the factors influencing secondary aerosol formation in the upper boundary layer in South Central China, size-segregated aerosol samples were collected using a micro-orifice uniform deposit impactor (MOUDI) in spring 2009 at the summit of Mount Heng (1269 m asl), followed by subsequent laboratory analyses of 13 inorganic and organic water-soluble ions. During non-dust-storm periods, the average PM1.8concentration was 41.8 μg·m-3, contributing to 55% of the PM10. Sulfates, nitrates, and ammonium, the dominant ions in the fine particles, amounted to 46.8% of the PM1.8. Compared with Mount Tai in the North China Plain, the concentrations of both fine and coarse particles and the ions contained therein were substantially lower. When the air masses from Southeast Asia prevailed, intensive biomass burning there led to elevated concentrations of sulfates, nitrates, ammonium, potassium, and chloride in the fine particles at Mount Heng. The air masses originating from the north Gobi brought heavy dust storms that resulted in the remarkable production of sulfates, ammonium, methane sulfonic acid, and oxalates in the coarse particles. Generally, the sulfates were primarily produced in the form of (NH4)2SO4in the droplet mode via heterogeneous aqueous reactions. Only approximately one-third of the nitrates were distributed in the fine mode, and high humidity facilitated the secondary formation of fine nitrates. The heterogeneous formation of coarse nitrates and ammonium on dry alkaline dust surfaces was found to be less efficient than that on the coarse particles during non-dust-storm periods.
Original languageEnglish
Pages (from-to)815-826
Number of pages12
JournalFrontiers of Environmental Science and Engineering
Volume7
Issue number6
DOIs
Publication statusPublished - 1 Dec 2013

Keywords

  • aerosol water-soluble ions
  • dust storm
  • Mount Heng
  • secondary formation
  • size distributions

ASJC Scopus subject areas

  • Environmental Science(all)

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