title: Associations Between Fine Particulate Matter Components and Daily Mortality in Nagoya, Japan.
abstract: BACKGROUND
  Seasonal variation and regional heterogeneity have been observed in the estimated effect of fine particulate matter (PM2.5) mass on mortality. Differences in the chemical compositions of PM2.5 may cause this variation. We investigated the association of the daily concentration of PM2.5 components with mortality in Nagoya, Japan.
  
  
  METHODS
  We combined daily mortality counts for all residents aged 65 years and older with concentration data for PM2.5 mass and components in Nagoya from April 2003 to December 2007. A time-stratified case-crossover design was used to examine the association of daily mortality with PM2.5 mass and each component (chloride, nitrate, sulfate, sodium, potassium, calcium, magnesium, ammonium, elemental carbon [EC], and organic carbon [OC]).
  
  
  RESULTS
  We found a stronger association between mortality and PM2.5 mass in transitional seasons. In analysis for each PM2.5 component, sulfate, nitrate, chloride, ammonium, potassium, EC, and OC were significantly associated with mortality in a single-pollutant model. In a multi-pollutant model, an interquartile range increase in the concentration of sulfate was marginally associated with an increase in all-cause mortality of 2.1% (95% confidence interval, -0.1 to 4.4).
  
  
  CONCLUSIONS
  These findings suggest that some specific PM components have a more hazardous effect than others and contribute to seasonal variation in the health effects of PM2.5.
authors.affiliation: Department of Engineering, Graduate School of Kyoto University.
authors.forename: Kayo
authors.initials: K
authors.lastname: Ueda
authors.forename: Makiko
authors.initials: M
authors.lastname: Yamagami
authors.forename: Fumikazu
authors.initials: F
authors.lastname: Ikemori
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Hisatsune
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nitta
mesh_terms: D000368:Aged; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D009026:Mortality; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D012621:Seasons
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter