Changes in black carbon and PM2.5 in Tokyo in 2003-2017

Tatsuhiro Mori, Sho Ohata, Yu Morino, Makoto Koike, Nobuhiro Moteki, Yutaka Kondo

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Black carbon (BC) particles cause adverse health effects and contribute to the heating of the atmosphere by absorbing visible solar radiation. Efforts have been made to reduce BC emissions, especially in urban areas; however, long-term measurements of BC mass concentration (MBC) are very limited in Japan. We report MBC measurements conducted in Tokyo from 2003 to 2017, showing that MBC decreased by a factor of 3 from 2003 to 2010 and was stable from 2010 to 2017. Fine particulate concentrations (PM2.5) decreased by a much smaller factor during 2003-2010. The diurnal variations of BC size distributions suggest that the BC in Tokyo originates mainly from local sources, even after 2010. Our three-dimensional model calculations show that BC from the Asian continent contributes a small portion (about 20%) of the annual average MBC in the Kanto region of Japan, which includes Tokyo. This indicates that continued reduction of BC emissions inside Japan should be effective in further decreasing MBC.

Original languageEnglish
Pages (from-to)122-129
Number of pages8
JournalProceedings of the Japan Academy Series B: Physical and Biological Sciences
Issue number3
Publication statusPublished - 2020
Externally publishedYes


  • Asia
  • Black carbon
  • PAHs
  • PM
  • Tokyo
  • Vehicular emission

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences
  • General Physics and Astronomy


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