Associations of acute exposure to fine and coarse particulate matter and mortality among older people in Tokyo, Japan

Takashi Yorifuji, Saori Kashima, Hiroyuki Doi

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37 Citations (Scopus)


Recent studies have reported adverse health effects of short-term exposure to coarse particles independent of particulate matter less than 2.5μm in diameter (PM2.5), but evidence in Asian countries is limited. We therefore evaluated associations between short-term exposure to particulate matter (PM) and mortality among older people in Tokyo, Japan. We used a time-stratified, case-crossover design. Study participants included 664,509 older people (≥65years old) in the 23 urbanized wards of the Tokyo Metropolitan Government, who died between January 2002 and December 2013. We obtained PM2.5 and suspended particulate matter (SPM; PM<7μm in diameter) from one general monitoring station. We calculated PM7-2.5 by subtracting PM2.5 from SPM to account for coarse particles. We then used conditional logistic regression to estimate odds ratios (ORs) and 95 confidence intervals (CIs). Same-day PM2.5 and PM7-2.5 were independently associated with all-cause and cause-specific mortality related to cardiovascular and respiratory diseases; for example, both pollutants were positively associated with increased risk of all-cause mortality even after simultaneous adjustment for each pollutant: OR of 1.006 (95% CI: 1.003, 1.009) for PM2.5 and 1.016 (95% CI: 1.011, 1.022) for PM7-2.5. Even below concentrations stipulated by the Japanese air quality guidelines for PM2.5 and SPM (PM7), we observed adverse health effects. This study provides further evidence that acute exposure to PM2.5 and coarse particles is associated with increased risk of mortality among older people. Rigorous evaluation of air quality guidelines for daily average PM2.5 and larger particles should be continued.

Original languageEnglish
Pages (from-to)354-359
Number of pages6
JournalScience of the Total Environment
Publication statusPublished - Jan 15 2016


  • Air pollution
  • Cardiovascular disease
  • Epidemiology
  • Mortality
  • Particulate matter
  • Respiratory disease

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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