日本海沿岸で粒径別連続採取したエアロゾル中の水可溶性イオン種および微量金属成分による長距離輸送現象の解析 : 2002年春の黄砂イベントを中心に [in Japanese] Analysis of Long-Range Transport of Aerosols with Water-Soluble Ionic Species and Trace Metal Components, Collected Continuously with Particle Size Segregation in the Coastal Area of the Sea of Japan : Focusing on the Kosa Event in Spring 2002 [in Japanese]
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We performed long-term continuous monitoring of aerosols at Tango Peninsula (Kyoto Prefecture) , in the coastal area of the Sea of Japan. We conducted long-term automatic continuous collection of aerosols with particle size segregation (<2.5μm and 2.5∼10μm) by means of a tape filter. A high-sensitivity inductively coupled Argon plasma mass spectrometer was used for the trace metal analysis. With this system, we could analyze trace metal concentrations from half-day or one-day samples of aerosols. High time resolution data of trace metal concentrations as well as trace metal concentration ratios can be used to evaluate long-range transport. A heavy Kosa event was observed in March and April 2002. We compared the variations in the concentrations of water-soluble inorganic ions as well as the trace metal components during the Kosa event with those collected during non-Kosa periods. Sulfate and ammonium ions, present as (NH<SUB>4</SUB>)<SUB>2</SUB>SO<SUB>4</SUB>, were the major water-soluble inorganic ions in aerosol particles with the diameter of less than 2.5μm, indicating that neutralization had advanced greatly. Chlorine loss was observed in aerosol particles of 2.5∼10μm in diameter during the non-Kosa period. There was a clear difference between soil-originated and anthropogenic trace metal components. During Kosa events, concentrations of almost all trace metals increased ; however, sometimes an increase in the anthropogenic trace metal component was observed without a corresponding increase in the soil-originated trace metal component. From backward trajectory analysis, when sulfate and lead concentrations were both high, the air mass had traveled from central China, and then across the Bohai and Yellow seas and the Korean Peninsula. Concentration ratios of Pb / Cd and Th / U showed characteristic values in the case of a Kosa event when the air mass had traveled over central China and the Korean Peninsula. Thus, trace metal concentration ratios are valuable for evaluating long-range aerosol transport.
- Earozoru Kenkyu
Earozoru Kenkyu 21(2), 160-175, 2006-06-20
Japan Association of Aerosol Science and Technology