Mineralogical characterization of suspended particulate matter collected at Yokohama and its vicinities from 1990 to 1994

Aerosol samples were collected with high-volume air-samplers at the Yokohama National University (YNU) campus from September, 1990 to November, 1994, and at Fujisawa and Nebukawa from February, 1993 to February, 1994. The data suggest that the SPM abundance at YNU has decreased since 1992. An average SPM abundance in the sample collected at YNU during 1993 is about 0.026mg/m^3. Mineralogical characteristics were examined for micron-size particles in the aerosol samples with SEM-EDS, XRD, and "Yokogawa Particle Analyzer System". Quartz, calcite, halite, gypsum, feldspar, magnetite, illite, kaolin, cristobalite, mullite, and sal ammoniac are commom constituents in the collected samples, together with minor amounts of talc, SiC, Si, flyash, olivine, amphibole, pyrite, apatite, mica, chlorite, Na-sulfate, and metallic iron spherule. The results indicate that most of micron-size carbon particles in the SPM sample are elemental carbon of sub-micron size. Elemental carbon and sulfur-bearing compounds of sub-micron size, and needle-like gypsum crystals are commonly attached on the surface of relatively coarse particles