A novel approach to identifying the elemental composition of individual residue particles retained in single snow crystals.

This study was carried out to describe the chemical characteristics of individual residual particles in hexagonal snow crystals, which can provide a clue to the aerosol removal mechanism during snowfall. In the present study, to collect snow crystal individually and to identify the elemental composition of individual residues retained in a hexagonal crystal, an orchestration of the replication technique and micro-particle induced X-ray emission (micro-PIXE) analysis was carried out. Information concerning the elemental compositions and their abundance in the snow crystals showed a severe crystal-to-crystal fluctuation. The residues retained in the hexagonal snow crystals were dominated primarily by mineral components, such as silica and calcium. Based on the elemental mask and the spectrum of micro-PIXE, it was possible to presume the chemical inner-structure as well as the elemental mixing state in and/or on the individual residues retained in single snow crystals.