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.

中文翻译：

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2003-2017年东京的黑碳和PM2.5的变化。

炭黑（BC）颗粒会导致不良的健康影响，并通过吸收可见的太阳辐射来促进大气的加热。已经做出努力减少卑诗省的排放，特别是在城市地区；但是，在日本，长期测量BC的质量浓度（MBC）非常有限。我们报告了2003年至2017年在东京进行的MBC测量，结果显示MBC从2003年至2010年下降了3倍，并且从2010年到2017年保持稳定。2003年以来，细颗粒物浓度（PM2.5）下降的幅度小得多。 2010。BC大小分布的日变化表明，即使在2010年之后，东京的BC也主要源自本地资源。我们的三维模型计算结果表明，亚洲大陆的卑诗省占日本关东地区（包括东京）的年平均MBC的一小部分（约20％）。这表明，继续减少日本国内的不列颠哥伦比亚省排放量应能有效地进一步减少MBC。