Abstract
Seasonal changes of water-insoluble, soluble and gaseous F concentrations of aerosols in day and night times from June, 1988 to April, 1989 in a non-industrial area, were investigated in Morioka, Northeast Japan. The water-insoluble and soluble F concentrations were higher from November to April than from June to October. On the contrary, the gaseous F concentration was high in summer, probably because of influences of the steel industrial area in the Pacific coast region and wind-blown sea salt from the Pacific Ocean. The water-soluble F concentration of aerosols from Changchun, Northeast China in March and July to December, 1991,which are mainly due to coal soot, was extremely high in the winter season and was 116 times higher than that from Morioka. In addition, Holocene, Malan and Lishi Loesses, loess-derived soils, and saline soils from Xinjian Uygur Zizhiqu, the Loess Plateau, and Northeast China, where there is a high incidence of endemic fluorosis, contained a considerable amount of water-soluble F. However, the amount of water-soluble F in loess-derived soils from Korea and Japan was very low, indicating that F was leached out by heavy rainfall. The aerosols collected at Morioka from winter to spring contained a significant amount of coal soot and eolian dust. The F concentration of aerosols in Japan, therefore, could be influenced by coal soot and eolian dust transported from the Asian continent. These airborne particles could affect the water-insoluble and soluble F concentrations of aerosols in Japan.
