[A-AS04] 大気化学

[AAS04-03] 沖縄県辺戸岬において2012年春季に見られた高濃度硫酸塩の発生源寄与評価

*板橋 秀一¹、畠山 史郎²、島田 幸治郎³、高見 昭憲⁴ (1.電力中央研究所、2.埼玉県環境科学国際センター、3.早稲田大学理工学術院創造理工学部環境資源工学科、4.国立環境研究所)

キーワード：硫酸塩、発生源寄与、大気質モデル

Air quality in Asia can cause regional-to-global environmental issues. Intensive observation campaigns approximately 1 week long have been conducted periodically from March 2010 to November 2015 at Cape Hedo, Okinawa, Japan. The period-averaged sulfate aerosol (SO₄^2-) concentrations for each campaign ranged from 0.34 to 6.97 μg m^-3, and the average concentration of all observations was 3.13 μg m^-3. The maximum daily mean concentrations surpassed 15 μg m^-3 in springtime 2012. The sources of this high SO₄^2- concentrations were estimated by using the air quality model with the tagged tracer method in this study. The main source of the high SO₄^2- concentrations in March was volcanoes and that in April was anthropogenic emissions from China. In March, the prevailing northerly wind transported a volcanic SO₂ plume with a low conversion ratio to Cape Hedo. The impacts of 15 volcanoes in Japan were estimated in this study, and a substantial impact of Sakurajima, which accounted for more SO₂ than anthropogenic emissions from Japan, was found. Throughout April, source apportionments from anthropogenic emissions from China were found; hence, the source was further divided into 31 provincial scales. Shandong and Jiangsu provinces, which are the first and seventh largest emission sources in China, were identified as important sources at Cape Hedo. These sources showed day-to-day variation, and the highest contribution from Shandong province was on April 23, whereas that from Jiangsu province was on April 22.