Study on Rapid Screening Methods for Asbestos in Disaster Debris

摘要

Rapid screening methods for asbestos in disaster debris by polarized light microscopy (PLM) and near-infrared spectrometry (NIR) were investigated. In PLM method, disaster debris samples were initially observed with a stereomicroscope to find any fibrous materials. If fibrous materials were found, they were observed by PLM to identify whether they were asbestos or not. The validity of these PLM and NIR methods was confirmed by a field test performed at a disaster waste depot site. Thirty-two debris samples were collected and analyzed by PLM and NIR methods. The screening results were evaluated by comparing the results obtained by a conventional old JIS method. It was confirmed that these rapid screening methods were sufficiently reliable for the on-site screening of asbestos because they presented high correct answer rates (94 % for PLM and 88 % for NIR). Though these methods sometimes reported false negatives for samples of which asbestos concentrations were below 3 %, they can be used for on-site screening because almost all building materials contain asbestos of more than 5 %. The screening periods per sample were about 15 minute for PLM method and about 1 minute for NIR method. Both PLM and NIR methods can be used for on-site rapid screening for asbestos in disaster debris or damaged buildings.