Remote monitoring of airborne asbestos particles using laser-induced fluorescence imaging

Ozu, Akira  ; Esaka, Fumitaka  ; Kawakita, Hiroshi*; Okamoto, Ryuta*; Imaki, Masaharu*; Kobayashi, Takao*

We have demonstrated that asbestos particles in air can be visualized with laser-induced fluorescence emitted from asbestos. A ultra-violet (266 nm) laser pulse is used to excite asbestos particles suspended in a closed vessel. The fluorescence emitted from the asbestos in the region where the laser beam passes through is detected with a low-pass optical filter and an image intensified CCD camera with ultra-fast gate shutter. Many asbestos particles in the region are separately visualized on an image. It is possible to derive from the image the number and size of asbestos particles through image data processing. The method described in this study is expected to be useful in real-time monitoring of the concentration of asbestos particle.