Contactless elemental and size analytical system for nanosized suspended particulate matter using LIBS and LII techniques

This paper presents a non-contact sensing system for nanosized suspended particulate matter (SPM) measurements using laser-induced incandescence (LII) and laser-induced breakdown spectroscopy (LIBS). The elemental composition and density of the SPMs are determined using LIBS, and particulate size measurements are accomplished using LII. Typically, temporally resolved LII enables measurement of soot particulate sizes in a combustion process. In the case of the measured object consisting of a single element material, it is easy to determine the particulate sizes distribution derived from the ratio of emission attenuation signals after a laser pulse, because the cooling behaviour is characteristic of the particulate size in LII technique. However, in actuality, the SPMs consist of several different types of elements. The elemental analysis using LIBS also allows correcting the discrepancy between the LII simulation values and observation results.