Characterization of spatially homogeneous regions based on temporal patterns of fine particulate matter in the continental United States

Seoung Bum Kim, Chivalai Temiyasathit, Victoria C P Chen, Sun Kyoung Park, Melanie Sattler, Armistead G. Russell

Research output: Contribution to journalArticle

22 Citations (Scopus)


Statistical analyses of time-series or spatial data have been widely used to investigate the behavior of ambient air pollutants. Because air pollution data are generally collected in a wide area of interest over a relatively long period, such analyses should take into account both spatial and temporal characteristics. The objective of this study is 2-fold: (1) to identify an efficient way to characterize the spatial variations of fine particulate matter (PM2.5) concentrations based solely upon their temporal patterns, and (2) to analyze the temporal and seasonal patterns of PM2.5 concentrations in spatially homogenous regions. This study used 24-hr average PM2.5 concentrations measured every third day during a period between 2001 and 2005 at 522 monitoring sites in the continental United States. A k-means clustering algorithm using the correlation distance was used to investigate the similarity in patterns between temporal profiles observed at the monitoring sites. A k-means clustering analysis produced six clusters of sites with distinct temporal patterns that were able to identify and characterize spatially homogeneous regions of the United States. The study also presents a rotated principal component analysis (RPCA) that has been used for characterizing spatial patterns of air pollution and discusses the difference between the clustering algorithm and RPCA.

Original languageEnglish
Pages (from-to)965-975
Number of pages11
JournalJournal of the Air and Waste Management Association
Issue number7
Publication statusPublished - 2008 Jul 1
Externally publishedYes


ASJC Scopus subject areas

  • Atmospheric Science
  • Waste Management and Disposal
  • Environmental Engineering
  • Environmental Science(all)
  • Environmental Chemistry

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