Identification of asbestos by laser-induced fluorescence microscopy

Ozu, Akira  ; Esaka, Fumitaka  ; Yasuda, Kenichiro   

Microscopic studies on laser-induced fluorescence emitted from asbestos (chrysotile) and a building material (glass-wool: a substitute material for asbestos) fibrous particle excited by a ultra-violet (266 nm) laser, have been conducted by visualizing those particles with the fluorescence. The fluorescence characteristics observed under the microscope agreed approximately with those observed in the determination using bulk samples. The decay ratio of the fluorescence intensity at 540 nm and other wavelength was in good agreement with that with bulk sample. The total amount of the intensity of glass-wool per unit area at 350 nm was 23 times larger than that of chrysotile, corresponding to that with bulk sample. A practical microscopic method used to discriminate asbestos by combining the decay ratio and total amount of the intensity are proposed.