Feasibility study on identification of asbestos using laser-induced fluorescence

Ozu, Akira  ; Esaka, Fumitaka  ; Yasuda, Kenichiro   

Laser-induced fluorescence of asbestos and several kinds of building materials such as glass-wools and talc, etc., have been studied for discriminating asbestos from the other materials. The fluorescence spectrums excited by ultra-violet (266 nm) laser pulse were observed over the wavelength range 350 to 700 nm, and the difference of the spectrum in shape between asbestos and the other materials was identified. The lifetime and relative intensity of the fluorescence emitted from those materials were also investigated and evaluated for the numerical discrimination of asbestos. Novel methods are presented for discriminating asbestos by comparing the relative ratio of the fluorescence intensity between two different ranges (430 and 575 nm) of the wavelength, and/or the lifetime and the total amount of the fluorescence. Applications of the method to conventional particle measurement systems, as examples, a microscopic method and an optical particle counter, are discussed.