Asbestos discrimination based on spectral analysis of laser-induced fluorescence

Ozu, Akira  ; Esaka, Fumitaka  ; Yasuda, Kenichiro   

Laser-induced fluorescence of three kinds of asbestos, fibrous building materials, and non-fibrous building materials were studied for asbestos discrimination. Lifetimes and relative intensity of the fluorescence from those materials excited by ultra-violet pulse laser of 266 nm were investigated. It was observed that the fluorescence of those materials was nearly made of two lifetimes (short and long) and the lifetime was changed with measured wavelength. The total amount of the fluorescence from chrysotile was around 10 times larger than that of crocidolite and amosite, and far smaller (1/45) than that of glass wool. Significant difference of the lifetime and intensity among those materials was identified. The discrimination methods using the difference of the decay ratio of the fluorescence intensity and the total amount of the fluorescence are discussed and the applications of those methods for microscopic analysis and optical particle measurement system are presented.