Determination of asbestos cement rooftop surface composition using regression analysis and hyper-spectral reflectance data in the visible and near-infrared ranges.

The effects of asbestos on human health have spurred numerous studies examining its risks in urban environments. Recent works have shifted towards less-invasive techniques for remote detection and classification of asbestos-cement. In this context, this study combines visible (VIS) and near-infrared (NIR) reflectance data collected in-situ with reference signals from the USGS spectral library, utilizing optimized regression analysis to determine the surface composition of corrugated asbestos-cement rooftops. An outlier filter was successfully implemented to enhance the accuracy of regression calculations, achieving a high level of agreement with actual field observations. The regression analysis revealed varying proportions of weathered cement, hazardous asbestos fibers (specifically chrysotile and cummingtonite), and biological growth (such as lichens and moss). These results are consistent with previous research on the composition of asbestos-cement rooftops, including a comparable field study and XRD analysis conducted in 2019. This underscores the importance of using regression analysis, preceded by an outlier filtering step, on VIS and NIR reflectance data to ascertain the surface composition of asbestos-cement rooftops. This methodology holds potential for application to larger hyperspectral datasets across more extensive sample surfaces and areas. [Display omitted] • Asbestos-cement (AC) surface composition can be assessed using reflectance analysis in the visible and near-infrared ranges. • Regression analysis can determine the surface composition of AC corrugated rooftop sheets. • Outlier detection applied to raw data can enhance the regression analysis to become comparable to in-situ observations. • Non-invasive identification and surface composition assessment of AC material is essential for the protection of human health. • The assessment of AC surfaces contributes to "sustainable cities and communities", a part of sustainable development goals. [ABSTRACT FROM AUTHOR]