Elucidation of aging process of aerosols containing iron of combustion origin: an approach using land-sea breeze circulation

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K12297
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: Hiroshima University
• Principal Investigator: IWAMOTO Yoko 広島大学, 統合生命科学研究科(生), 准教授 (60599645)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 燃焼起源エアロゾル / 微量金属成分 / 主要イオン成分 / 粒径分布 / 濃縮係数 / 固定発生源 / 瀬戸内海

Outline of Final Research Achievements

To elucidate the aging process of atmospheric aerosol particles containing iron of combustion origin, we analyzed atmospheric aerosol samples collected at a coastal site near the source of iron of combustion origin and at an inland site affected by land-sea breeze circulation. The concentration of water-soluble Fe was highly correlated with that of non-sea salt sulfate, indicating that anthropogenic contribution is significant. In addition, it was confirmed that mixing of water-soluble Fe with anthropogenic sulfate, i.e., aging process, proceeded during transport from the correlation of concentration with multiple components and morphological observation. A steel mill, a major stationary source of iron of combustion origin near the coastal site, shut down its blast furnace during the observation period. As a result, the total and water-soluble iron in aerosols at the coastal site decreased by 70% and 53%, respectively.

Free Research Field

大気海洋化学

Academic Significance and Societal Importance of the Research Achievements

鉄は、海洋による炭素吸収の一部を担う植物プランクトンの生長を支える必須元素である。大気中の燃焼起源鉄は人為起源の酸性物質と共存する機会が多く、より溶けやすい生物利用可能な鉄の海洋への供給源として着目されている。本研究課題は燃焼起源鉄の主要な発生源に近い瀬戸内海の沿岸サイトと海陸風循環の影響を受ける内陸サイトにおいて、大気中の鉄を含む微粒子の動態を観測し、大気輸送中に燃焼起源鉄と人為起源の酸性物質との混合が進むことを確かめた。また、製鉄所の高炉停止という燃焼起源鉄の主要な発生源の消失が、大気エアロゾル中の鉄濃度を顕著に減少させることを確かめた。