@article{102f4e86e41d482bbf6cacb9a61c3675,
title = "Changes in black carbon and PM2.5 in Tokyo in 2003-2017",
abstract = "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.",
keywords = "Asia, Black carbon, PAHs, PM, Tokyo, Vehicular emission",
author = "Tatsuhiro Mori and Sho Ohata and Yu Morino and Makoto Koike and Nobuhiro Moteki and Yutaka Kondo",
note = "Funding Information: We thank Jun-ichi Kurokawa of the Asia Center for Air Pollution Research for providing the BC emission rate data from different sectors in Japan. We also thank Kazuichi Hayakawa of Kanazawa University for providing the PAHs data for Kanto. This work was supported by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT), the Environment Research and Technology Development Fund (2-1403 and 2-1703) of the Environmental Restoration and Conservation Agency of Japan, Japan Society for the Promotion of Science KAKENHI Grant (JP16H01770), and the Arctic Challenge for Sustainability project. The data used in this study are available at URL (https:// ads.nipr.ac.jp/dataset/A20191212-002). Funding Information: We thank Jun-ichi Kurokawa of the Asia Center for Air Pollution Research for providing the BC emission rate data from different sectors in Japan. We also thank Kazuichi Hayakawa of Kanazawa University for providing the PAHs data for Kanto. This work was supported by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT), the Environment Research and Technology Development Fund (2-1403 and 2-1703) of the Environmental Restoration and Conservation Agency of Japan, Japan Society for the Promotion of Science KAKENHI Grant (JP16H01770), and the Arctic Challenge for Sustainability project. The data used in this study are available at URL (https://ads.nipr.ac.jp/dataset/A20191212-002). Publisher Copyright: {\textcopyright} 2020 The Japan Academy.",
year = "2020",
doi = "10.2183/PJAB.96.010",
language = "English",
volume = "96",
pages = "122--129",
journal = "Proceedings of the Japan Academy Series B: Physical and Biological Sciences",
issn = "0386-2208",
publisher = "Japan Academy",
number = "3",
}