Identification, mapping, and quantification of asbestos minerals in ACM and NOA using NIR-SWIR hyperspectral scan...

Here, we aimed at extending the Near Infrared-Short-wave infrared (NIR-SWIR) spectroscopy approach in characterizing Asbestos Containing Materials (ACM) and Natural Occurring Asbestos (NOA) through the development and testing of a novel portable asbestos mapping tool based on Hyperspectral Imaging (NIR-HSI) tool. This was built using high resolution spectroscopy over a range of about 170 nm around the OH overtone bands (about 1370-1420 nm), a supercontinuum laser for vibrational excitation, compact XYZ translation stages, and dedicated software. The vibrational reflection data measured using this system allowed discriminating different asbestos minerals and to define the methodological basis for their quantification in various matrices. Point scan NIR-SWIR reflectance images with a spatial resolution of about 50 µm allowed successfully mapping asbestos inclusion in proximity of the surface of a set of samples. The experimentation demonstrated the possibility of characterizing asbestos in NOA or ACM directly in situ, through mineral mapping providing qualitative and semi-quantitative information on the asbestos fiber contents.