Spatial distribution and seasonal variation of char-EC and soot-EC in the atmosphere over China

Y. M. Han, Shuncheng Lee, J. J. Cao, K. F. Ho, Z. S. An

Research output: Journal article publicationJournal articleAcademic researchpeer-review

128 Citations (Scopus)


A previous study on PM2.5carbonaceous aerosols measured with the thermal optical reflectance (TOR) method in fourteen Chinese cities is extended by subdividing total EC into char-EC and soot-EC. Average char-EC concentrations show great differences between the fourteen cities and between winter and summer periods, with concentrations of 8.67 and 2.41 μg m-3in winter and summer, respectively. Meanwhile spatial and seasonal soot-EC variations are small, with average concentrations of 1.26 and 1.21 μg m-3in winter and summer, respectively. Spatial and temporal distributions of char-EC, similar to EC, are mainly influenced by local fuel consumption, as well as the East Asian monsoon and some meteorological factors such as the mixing height and wet precipitation. The small spatial and seasonal variation of soot-EC is consistent with its regional-to-global dispersion, which may suggest that soot carbon is not local carbon, but regional carbon. Char-EC/soot-EC ratios show summer minimum and winter maximum in all cities, which is in good agreement with the difference in source contributions between the two periods. As OC/EC ratio is affected by the formation of the secondary organic aerosol (SOA), char-EC/soot-EC ratio is a more effective indicator for source identification of carbonaceous aerosol than previously used OC/EC ratio.
Original languageEnglish
Pages (from-to)6066-6073
Number of pages8
JournalAtmospheric Environment
Issue number38
Publication statusPublished - 1 Oct 2009


  • Carbonaceous aerosols
  • Char
  • China
  • Soot
  • Spatial distribution

ASJC Scopus subject areas

  • General Environmental Science
  • Atmospheric Science


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