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In order to shed light on the long-range transport of atmospheric pollutants in the Northeast Asian regions, we studied the chemical components in rime and fresh surface snow on Mt. Moriyoshi (altitude: 1454 m), located on the Sea of Japan side of northern Honshu, Japan, near Northwest China and Southwest Russia. Rime and fresh surface snow samples were collected at Juhyou-Daira (near the summit; altitude: 1200 m) in February 2004. The pH range of rime samples was 4.2 – 4.9, and the electric conductivity (EC) range was 52 – 282 μS/cm. On the other hand, the pH range of snow samples was 4.5 – 4.9, and the EC range was 17 – 77 μS/cm. The elemental compositions, ionic species and particle shapes of these samples were determined and/or observed by PIXE, ion chromatography and SEM-EDX analysis. PIXE analysis of the rime and snow samples revealed 24 elements, of which Na, Mg, Al, Si, K, Ca, Ti and Fe were found to be the major components. Comparing the determined values of rime and snow sample elements, rime samples were several times to several dozen times higher than snow samples for almost all the elements. For determined values of ionic species, rime samples were several times to several dozen times higher than snow samples. With the aid of SEM-EDX analysis, many small silicon-rich spherical particles were observed in the rime samples. Small silicon-rich spherical particles were also found in the snow samples. The existent forms of chemical components in rime will be an important factor when we consider the origin of air pollutants transported over long distances in the Northeast Asian regions.

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.

Lichens have been used extensively as biomonitors of air quality (Richardson 1992; Seaward 1995, 2005). Lichen thalli lack a protective layer and hence accumulate airborne pollutants and particulate matter from the environment by wet and dry deposition (Nash 1996). The elements accumulated on lichen thalli can be quantitatively analysed using techniques such as Proton Induced X-ray Emission (PIXE) and Electron probe microanalysis. These techniques yield two-dimensional, quantitative element information with micron-level spatial resolution. This study used Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) and PIXE to quantify elements accumulated on lichen thalli of selected species collected from polluted and unpolluted areas of the Madukkarai – Walayar forests. Thalli of selected lichen species from the study site (polluted and unpolluted) were irradiated using 1.7 MV tandem accelerator with Proton beam energy of 2 MeV. The ion induced X-rays were detected by Si (Li) semiconductor detector. The morphological analysis and localization of elements accumulated on these lichen samples were also carried out with the use of a SEM-EDX microanalysis using environmental scanning electron microscopy (ESEM) as supporting evidence. PIXE spectral elemental output revealed the presence of elements such as As, Ba, Br, Ca, Cu, Fe, K, Mn, Zn, Cl, Ti, Cr and Pd with the incidence of increased Calcium levels. IAEA 336 lichen reference material was used for standardization.

The characteristics of the road-side particles were examined. The elemental concentrations of aerosol particle collected on the road-side were measured both by PIXE analysis as a bulk sample and SEM-EDX analysis as individual particle sample. For the data set of SEM-EDX, cluster analysis was applied.

On an average, more than 80% of the aerosol particles are consisted of lighter elements such as C, O, N and H. Main metal components contained in the roadside particles were Si, Ca, Fe and Al that were mainly originated in soil.

Two kinds of α-Fe₂O₃ catalysts supported on χ-Al₂O₃ and γ-Al₂O₃ were synthesized. α-Fe₂O₃ was prepared from α-FeOOH. As a model experiment, an investigation was made with the oxidation of methane. As all catalysts with various Fe contents supported on χ-Al₂O₃ with various Fe contents had higher specific surface areas than those supported on γ-Al₂O₃, α-Fe₂O₃/χ-Al₂O₃ catalyst has higher catalytic activities than α-Fe₂O₃/γ-Al₂O₃ catalyst. From SEM-EDS analyses, it is concluded that in α-Fe₂O₃/χ-Al₂O₃ catalyst, α-Fe₂O₃ exists mainly on the surface of the support, because of flatness of the surface of χ-Al₂O₃. On the other hand, in the case of α-Fe₂O₃/γ-Al₂O₃ catalyst, as the surface of support, γ-Al₂O₃, is uneven, α-Fe₂O₃ do not partially exist on the surface but in the pores.

Green synthesis of nanoparticles is rapidly evolving because it is cost-effective and eco-friendly, this also contributes to its preference over nanoparticles from other sources. In this study, silver nanoparticles were synthesized from Allium cepa (AC) and Raphanus sativus (RS) aqueous extracts and the biological activities were evaluated. The silver nanoparticles AgNPs@AC and AgNPS@RS were synthesized from AC and RS extracts, respectively, using silver nitrate and characterized using UV–visible spectroscopy (UV–Vis), Fourier transform infrared (FT-IR) spectroscopy, Powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). The FT-IR spectra of AgNPs@AC and AgNPS@RS showed characteristic groups pertaining to active molecules of the respective extracts indicating their surface functionalization. The XRD pattern of AgNPs@AC revealed diffraction peaks at 38.26, 44.39, 64.65, 77.54 and 81.64 that were indexed to (1 1 1), (2 0 0), (2 2 0), (3 1 1) and (2 2 2) planes of face-centered cubic (FCC) crystalline structure, respectively. The XRD pattern of AgNPs@RS revealed diffraction peaks at 38.24, 44.32, 64.62, 77.46 and 81.65 that was indexed to (1 1 1), (2 0 0), (2 2 0), (3 1 1) and (2 2 2) planes of face-centered cubic (FCC) crystalline structure, respectively. The SEM images indicate that the particles are spherical in shape and have particle size in the range of 25–35 nm. The nanoparticles demonstrated substantial antimicrobial activity against Gram +ve and Gram −ve harmful bacteria species, such as S. aureus, E. coli and fungal species C. albicans. This study shows that A. cepa (Onion) and R. sativus (Radish) aqueous extracts can be used as an effective reducing and capping agent for the green synthesis of silver nanoparticles (AgNP). AgNPS@RS showed acceptable size and shape of nanoparticles and could therefore be a potential source of antimicrobial agents.