Seasonal variations and mass closure analysis of particulate matter in Hong Kong

K. F. Ho, Shuncheng Lee, J. J. Cao, Judith C. Chow, John G. Watson, Chak K. Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

100 Citations (Scopus)


The chemical characteristics of ambient particulate matters in urban and rural areas of Hong Kong were determined in this study. A monitoring program starting from November 2000 to February 2001 (winter) and June 2001 to August 2001 (summer) for PM10and PM2.5was performed at three monitoring stations in Hong Kong. Twenty-four-hour PM10and PM2.5samples were collected once every 6 days at two urban sites, PolyU and KT, and every 12 days at a background site, HT, with Hi-Vol samplers. High concentrations of OC, EC (except in PolyU), water-soluble ions and elements were observed in winter among the three sampling sites for PM10and PM2.5fractions. Seasonal variations were significant in background HT. Dilution effect due to the increase in mixing depth and precipitation in summer reduced the concentrations of particulate matters. Long-range transport could contribute to the higher concentrations of particulate matter in the winter. Chemical mass closure calculations were performed for PM10and PM2.5observed. Mass closure improved when separate factors (1.4 and 1.9 respectively) were used to convert water-soluble organic carbon (WSOC) and water-insoluble organic carbon (WINSOC) into corresponding organic masses. The urban sites showed high percentages of water-soluble ions in winter and high percentages of carbonaceous species in summer. Better results were obtained for the chemical mass closure analysis in winter than in summer. High temperature and solar radiation in summer increased the rate of the complex photochemical reaction in the atmosphere. Therefore the chemical mass closure analysis would underestimate the volatized species and secondary aerosols during summer.
Original languageEnglish
Pages (from-to)276-287
Number of pages12
JournalScience of the Total Environment
Issue number1-3
Publication statusPublished - 15 Feb 2006


  • Carbonaceous species
  • Chemical mass closure
  • Hong Kong
  • Particulate matter
  • Water-soluble ions

ASJC Scopus subject areas

  • Environmental Chemistry
  • General Environmental Science


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