Abstract The atmospheric concentration of elemental carbon (EC) in aerosol particles is a key parameter related to global warming and health effects. Emission regulations for diesel exhaust intended to reduce EC concentrations have been strengthened in recent years. To investigate regulation effects in Japan, daily EC concentrations in the megacity of Nagoya, central Japan, were measured during April 2003–March 2016. The EC concentrations showed a decreasing trend with changing seasonal variation: high concentrations were found in autumn and winter before 2011, but no seasonal variation was discernible after 2012. Strong correlation was found for annual vehicular EC emissions and annual mean EC concentrations during 2003–2009. However, the relation after 2010 was weaker in spring and summer. Based on the relation of EC with trace element (Pb, V, Sb, etc.) concentrations and the backward air trajectories on high concentration days, EC sources other than vehicles were found to be related to long-range transport of air pollution from China in spring and combustion of heavy oil, including ship engine exhaust, in summer.

中文翻译：

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日本中部特大城市名古屋元素碳浓度随主要来源变化的下降趋势

摘要 气溶胶颗粒中元素碳 (EC) 的大气浓度是与全球变暖和健康影响相关的关键参数。近年来，旨在降低 EC 浓度的柴油机尾气排放法规得到了加强。为研究日本的调控效果，在 2003 年 4 月至 2016 年 3 月期间测量了日本中部名古屋特大城市的每日 EC 浓度。 EC 浓度随季节变化呈下降趋势：2011 年之前的秋冬季发现高浓度，但在 2012 年之后没有明显的季节性变化。在 2003-2009 年期间发现年度车辆 EC 排放量和年度平均 EC 浓度有很强的相关性。但2010年以后春夏两季的关系较弱。基于 EC 与微量元素（Pb、V、