Acute exposure to fine and coarse particulate matter and infant mortality in Tokyo, Japan (2002-2013)

Takashi Yorifuji, Saori Kashima, Hiroyuki Doi

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28 Citations (Scopus)


Few studies have evaluated the effect of short-term exposure to particulate matter (PM) less than 2.5 μm in diameter (PM 2.5 ) or to coarse particles on infant mortality. We evaluated the association between short-term exposure to PM and infant mortality in Japan and assessed whether adverse health effects were observable at PM concentrations below Japanese air quality guidelines. We used a time-stratified, case-crossover design. The participants included 2086 infants who died in the 23 urbanized wards of the Tokyo Metropolitan Government between January 2002 and December 2013. We obtained measures of PM 2.5 and suspended particulate matter (SPM; PM < 7 μm in diameter) from one general monitoring station. As a measure of coarse particles, we calculated PM 7-2.5 by subtracting PM 2.5 from SPM. We then used conditional logistic regression to analyze the data. Same-day PM 2.5 was associated with increased risks of infant and postneonatal mortality, especially for mortality related to respiratory causes. For a 10 μg/m 3 increase in PM 2.5 , the odds ratios were 1.06 (95% confidence interval: 1.01-1.12) for infant mortality and 1.10 (1.02-1.19) for postneonatal mortality. PM 7-2.5 was also associated with an increased risk of postneonatal mortality, independent of PM 2.5 . Even when PM 2.5 and SPM concentrations were below Japanese air quality guidelines, we observed adverse health effects. This study provides further evidence that acute exposure to PM 2.5 and coarse particles (PM 7-2.5 ) is associated with an increased risk of infant mortality. Further, rigorous evaluation of air quality guidelines for daily average PM 2.5 and larger particles is needed.

Original languageEnglish
Pages (from-to)66-72
Number of pages7
JournalScience of the Total Environment
Publication statusPublished - May 1 2016


  • Air pollution
  • Epidemiology
  • Infant mortality
  • Neonatal mortality
  • Particulate matter
  • Postneonatal mortality

ASJC Scopus subject areas

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


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