Interpretation of air quality in relation to monitoring station's surroundings

Jason Lau, W. T. Hung, Chun Shun Cheung

Research output: Journal article publicationJournal articleAcademic researchpeer-review

59 Citations (Scopus)


This study explores the appropriateness of the locality of air monitoring stations which are meant to indicate air quality in the area. Daily variations in NO2and PM10concentrations at 14 monitoring stations in Hong Kong are examined. The daily variations in NO2at a number of background monitoring stations exhibit patterns similar to variations in traffic volume while variations in PM10concentration exhibit less discernible pattern. Principal component analysis (PCA) and cluster analysis (CA) are applied to analyse NO2and PM10measurements between January 2001 and December 2005. The results show that NO2concentrations at background stations within the urban area are highly influenced by vehicle emissions. The effect vehicle emission has on NO2at stations within new towns is smaller. CA results also show that variations in PM10concentrations are distinguished by the area the station is located in. PCA results show that there are two principal components (PC's) associated with variations in roadside concentration of PM10. The strong influence of roadside emissions towards concentrations of NO2and PM10at a number of urban background stations may be due to their close proximity to busy roadways and the high density of surrounding tall buildings, which creates an enclosure that hinders dispersion of roadside emissions and results in air pollution behaviour that reflects variation in traffic.
Original languageEnglish
Pages (from-to)769-777
Number of pages9
JournalAtmospheric Environment
Issue number4
Publication statusPublished - 1 Feb 2009


  • Dispersion process
  • Monitoring station location
  • NO 2
  • PM 10
  • Roadside emission

ASJC Scopus subject areas

  • Atmospheric Science
  • General Environmental Science


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