Characterization of atmospheric aerosol particles in a mountainous region in northern Japan

In order to shed light on the long-range transport of atmospheric pollutants in the Northeast Asian Regions, we studied a multi-probe, chemical characterization and composition profile of airborne particulate matter (PM) on Mt. Moriyoshi (altitude 1454 m), located on the Sea of Japan side of northern Honshu, Japan. Sampling of size-resolved airborne PM was carried out on Juhyou-Daira (west side near the summit, altitude 1167 m) from February 1–16 (winter period) and July 7–19 (summer period) in 2004. Concentrations of several elemental and ionic species in each size-resolved PM sample were determined by particle-induced X-ray emission (PIXE) and ion chromatography analysis. From the winter period, results suggested that PM was formed from soil and sea salt particle sizes of PM10–PM2.5 and from ammonium sulfate particles, secondary particles < PM1.0. However from the summer period, results suggested that PM was formed from soil and sea salt particles > PM10–PM2.5 and secondary particles < PM1.0. With the aid of SEM-EDX analysis, many cubic particles were observed throughout the winter and summer periods. In particular, particles < PM1.0 were almost all cubic particles. Small spherical particles were mainly detected in PM10–PM2.5 and PM2.5–PM1.0 categories of the winter period. These cubic and small spherical particles were the silicon-rich type.