DEVELOPMENT OF METHODS FOR ANALYZING INORGANIC COMPONENTS IN AEROSOLS AND THEIR APPLICATION TO CHEMICAL CHARACTERIZATION OF ATMOSPHERIC AEROSOLS

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Spectromicroscopy using SR x-ray microprobe system was fabricated for single particle analysis. The system consists of elemental analysis by chemical state analysis of μ-XANES and crystal structure analysis by p,-XRD. The spatial resolution was 2-5μm and the minimum detection limit of Ni was 0.3fg for 10keV x-ray microbeam. The energy dependence of XRF yield enabled identification of the chemical states of elements from Cr to Zn with specific XANES spectra. In μ-XRD system, the sample was angularly oscillated with compensation of the beam displacements to obtain several indices of diffraction from a single particle. We have also developed a AgF-nitron double thin film method for simultaneous detection of chloride and nitrate ions in individual particles.The system was applied to quantify the ultra trace elements in the individual Kosa and non-Kosa aerosols collected at the two remote sites in Japan and Korea. We have demonstrated the remarkable mass increase of heavy elements (Mn, Ni, Cu, Zn) as well as soil components during Kosa event compared with non-Kosa period. Several time-series samplings were performed from the beginning of the Kosa incoming to investigate the mixing state of chloride, nitrate and sulfate ions in individual particles by two double thin film methods. It was revealed that sulfate constituted the majority of the formed components in the modified particles in Korea, while nitrate was the major component in Japan at Kosa event in the spring of 2004. Percentage of the modified particles roughly decreased with time and that of the particles containing both chloride and nitrate was largest at the first sampling with significant decrease after that time. In the modified coarse particles, nitrate was the dominant ions and particles containing both sulfate and nitrate were slightly detected. Particles containing all three ions were hardly detected.