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Total suspended particulate (TSP) samples were collected from three areas (commercial, residential and agricultural) in and near Akita City in northern Japan, from May – June 1996 (non-snow-clad period) and January – February 1997 (snow-clad period), over three days with a one-hour sampling interval for each area. The elemental composition and particle shape of TSP samples were determined and/or observed by Particle Induced X-ray Emission (PIXE) and a Scanning Electron Microscope (SEM) combined with Energy Dispersive X-ray (EDX) analysis. In the hourly TSP samples collected during the non-snow-clad period, 23 elements were determined for each area, and Na, Mg, Al, Si, S, Cl, K, Ca and Fe were the major components. On the other hand, 25 elements, excluding As and Rb, were found in the snow-clad period samples, and P, Ga, Nb and Mo were only found in the snow-clad-period samples. Dominant elements, i.e., major components, of the snow-clad period were the same as the non-snow-clad period. Comparing the arithmetic means of elemental concentrations in TSP for the non-snow-clad and snow-clad periods, in the commercial area the elemental concentrations in the snow-clad period were the same or lower than those in the non-snow-clad period, with the concentrations of Na, Mg, Al, Si, S, K, Ca, Ti and Fe in particular being markedly lower. In the residential area the concentrations of Na, Mg and Cl were markedly higher in the snow-clad period than in the non-snow-clad period, while the concentrations of the other elements were the same or only slightly lower. In the agricultural area, the concentrations of Na and Cl were markedly higher in the snow-clad period relative to the non-snow-clad period, and the concentrations of the other elements, except for P, were low. The concentrations of the major elements and Pb were particularly low. Thus, in the residential and agricultural areas the effect of northwesterly winter wind on TSP can be observed by Cl, and it is conjectured that soil particles rising up into the air is inhibited by snow accumulation. Soil particles rising up into the air seems to be inhibited by snow accumulation in the commercial area as well. With the aid of SEM and EDX analysis, aggregates of diesel exhaust particles (DEP), soil particles and small silicon-rich spherical particles were observed in the non-snow-clad and snow-clad period samples for each area. In addition, small aluminum-rich and iron-rich spheres were observed during the non-snow-clad period in the commercial area. Zinc-rich fiber was observed during the non-snow-clad period in the residential area.

Total suspended particulate (TSP) samples were collected from three areas (commercial, residential and agricultural) in and near Akita City in northern Japan, October 1996 (rice straw burning period), over three days with a one-hour sampling interval for each area. The elemental composition and particle shape of TSP samples were determined and/or observed by PIXE and a Scanning Electron Microscope (SEM) combined with Energy Dispersive X-ray (EDX) analysis. In the hourly TSP samples collected during the rice straw burning period, values of 24 elements were determined for each area, and Na, Mg, Al, Si, S, K, Ca and Fe were the major components. Comparing the arithmetic means of elemental concentrations in TSP for the rice straw burning and non-snow-clad period (May – June 1996), in the residential and agricultural areas the Si concentration in the rice straw burning period was approximately two times that in the non-snow-clad period, and K and Ca concentrations in the rice straw burning period were a little higher than those in the non-snow-clad period. In the residential and agricultural areas, change in SPM concentration and change in Si, K and Ca concentrations were in relative agreement during the hours that smoke from rice straw burning was present in the atmospheric space. With the aid of SEM- EDX analysis, many cubic particles were observed for almost all hourly TSP samples. The cubic particles were of the silicon-rich type, and their morphology was rice straw fragments or aggregation of fragments.

As part of a biomonitoring study of atmospheric particles for the development of a biological and environmental monitoring system in the beech (Fagus crenata Blume) forest ecosystem, we carried out elemental content and two-dimensional analysis of beech leaves by conventional PIXE and micro-PIXE. The beech leaves were collected from natural beech forests at eight locations in Japan. For conventional PIXE analysis of beech leaf samples, 27 elements were determined in total. Mg, P, S, K, Ca, Mn, Fe, Cu and Zn were found to be the important nutrient elements for plants at all sampling sites. According to radar chart analysis results for element (Mg, P, S, K, Ca, Mn, Fe, Cu and Zn) concentrations at each sampling site, K and P, Fe and Ca, and Zn and Cu showed relatively similar patterns. However, elements with a pattern similar to that of Mg, S, and Mn were not found. These elemental concentrations were largely different at beech leaf sampling sites. For micro-PIXE analysis of beech leaf samples from seven sampling sites (Soebetsu beech forest was excluded), scanning transmission ion microscopy (STIM) images and maps of Mg, Si, P, S, K, Ca, Mn and Fe were similar. In samples from Soebetsu beech forest, portions missing from the element distribution were observed. In particular, maps of Mg, Si, P, S, K and Ca were conspicuous. These analysis results may be important information for understanding the mechanism of plant metabolism.

In order to evaluate the quantitative values of atmospheric aerosol samples collected on filters, we investigated the effects of filter collection conditions (non-uniformity of collected particles) on analytical values and compared the quantitative values by means of PIXE and ICP-MS, using as the analytical sample PM_2.5 collected on filters in a monitoring survey of atmospheric fine aerosol over the Kanto area of Japan in summer 2013. The results were as follows: (i) With respect to the uniformity of filter collection, differences in concentrations were seen for S and Cl as well as elements thought to originate in soil (Al, Si, Ti and Fe) depending on the analysis point, suggesting that collection of sulfate particles, chloride particles, and soil particles on filters was not uniform. (ii) According to a comparison of quantitative values yielded by PIXE and ICP-MS, ICP-MS values were lower than PIXE values for Mg, Al, Si, Ti and Fe, with Mg and Si being markedly lower. On the other hand, ICP-MS values were higher than PIXE values for Na, K, Ca and Zn. (iii) According to the results of measurement of NIST reference material and PM_2.5 samples by means of PIXE and ICP-MS, Mg, Al, Si, Ca, Ti, Fe and Zn showed the same tendency. However, Na and K were opposite.