Comparison of electron microscope techniques for the identification of asbestos fibers

Six asbestos minerals and seven non-asbestos sheet and chain silicates were studied and the results from the two electron microscope methods were studied. The scanning electron microscope with energy dispersive x-ray microanalysis SEM-ED elemental spectra of the asbestos minerals were indistinguishable from certain of the non-asbestos minerals. In every case, the transmission electron microscope coupled with selected area electron diffraction (TEM-SAED) patterns showed characteristic layer line and spacing patterns for the asbestos minerals which were always distinguishable from the non-asbestos mineral. TEM-SAED analysis is therefore considered the only technique capable of identifying and sizing asbestos particles collected in a low concentration environment.