Basic Research on Elemental and Size Analytical System for Nano-Sized Suspended Particulate Matter Using Contactless Optical Measurement Techniques

A contactless sensing system for nano-sized carbonaceous particulate matter using laser-induced incandescence (LII) and laser-induced breakdown spectroscopy (LIBS) is presented. The LIBS technique allows detecting elemental composition and density of the SPMs, and LII technique allows to measure particulate size. LII technique is temporal resolved method that enables measurement of soot particulate sizes in a combustion process. In the case of the measured material consisting of a carbonaceous element, it is easy to determine the particulate diameter distribution derived from the time-profile of emission attenuation signals during cooling process, because the cooling behaviour is characteristic of the particulate diameter in LII technique. However, in actuality, the SPMs consist of several different types of elements. By using LIBS technique, the elemental analysis is able to conduct easily.