Chemical Composition of Subway Particles in Seoul, Korea, Determined Using Quantitative Single Particle Analysis

  • Hae-Jin Jung
  • Sunni Kang
  • Hye Kyeong Kim
  • Chul-Un RoEmail author
Part of the Environmental Science and Engineering book series (ESE)


A novel single particle analytical technique, called low-Z particle electron probe X-ray microanalysis, was applied to characterize seasonal indoor aerosol samples collected at a subway station in Seoul, Korea. Four major types of particles, based on their chemical compositions, are significantly encountered: Fe-containing; soil-derived; carbonaceous; and secondary nitrate and/or sulfate particles. Fe-containing particles are present in the greatest amounts, with a relative abundance in the range of 61–79%. Fe-containing particles are generated from wear processes at rail-wheel-brake interfaces, while the others may be introduced mostly from the outdoor urban atmosphere. Most of the Fe-containing particles are found in either a partially or fully oxidized state. The relative abundance of Fe-containing particles increases as particle size decreases. In samples collected in the summer, Fe-containing particles are the most abundantly encountered, whereas soil-derived and nitrate/sulfate particles are present in the lowest amounts. This indicates that the air-exchange between indoor and outdoor environments is limited in the summer, owing to the air-conditioning in the subway system. In addition, it was observed that the relative abundance of particles of outdoor origin vary somewhat among seasonal samples to a lesser degree, reflecting that indoor emission sources predominate. To clearly identify indoor source of subway particles, four sets of samples collected in the tunnel, at the platform, at the waiting room, and outdoors were investigated. For the samples collected in the tunnel, Fe-containing particles predominate. For the samples collected at the platform, at the waiting room, and outdoors, the relative abundance of Fe-containing particles decreases as the distance of the sampling sites from the tunnel increases. In addition, samples collected at the platform of a subway station, where there are screen doors that limit air-mixing between the platform and the tunnel, show a marked decrease in the relative abundance of Fe-containing particles. Clearly, this indicates that Fe-containing subway particles are generated in the tunnel.


PM10 Concentration Outdoor Environment Iron Oxide Particle Subway Station Carbonaceous Particle 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • Hae-Jin Jung
    • 1
  • Sunni Kang
    • 1
  • Hye Kyeong Kim
    • 1
  • Chul-Un Ro
    • 1
    Email author
  1. 1.Department of ChemistryInha UniversityNam-guKorea

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