CHARACTERIZATION OF ATMOSPHERIC AEROSOL IN THE NORTHERN FOOT OF MT. FUJI, CENTRAL JAPAN

摘要

The unique characteristics of atmospheric aerosol in the northern foot of Mt. Fuji, central Japan were first clarified. The Mt. Fuji (an altitute of 3776 m) is the largest basaltic stratovolcano in the quaternary period in Japan. The aerosol measurements were carried out at an altitute of 1100m from June 2000 to April 2001. Ambient aerosol in the predominant area of a typical volcanic rock like basalt was referred to as a basaltic aerosol in this study. Fifteen elements (Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Zn, Ba, Pb) of major to trace in the aerosol samples were determined by X-ray fluorescence spectrometry. Total mass concentration (< 10 μm) of the basaltic aerosol showed the higher values in summer and spring rather than autumn to winter, and the seasonal variation pattern differed widely from that of general urban aerosol. The behavior of the basaltic aerosol was mainly controlled by mineral particles throughout the year, so that a typical anthropogenic-derived element like Pb was very rarely detected. Even V, Cr and Zn which have been generally considered to be typical anthropogenic-derived elements, showed crustal-like behaviors. A concentration ratio of Si/Al showed markedly a uniqueness of the basaltic aerosol. From a comparison with atmospheric aerosol Si/Al ratio in granitic region being an exact opposite geology, a correlation plot of Si/Al ratio against Si concentration was made. It showed a big regional difference available for source identification of atmospheric soil particles. The chemical and geological characteristics of the basaltic aerosol are very useful for the novel characterization of atmospheric soil particles.