Which technique can provide a definitive identification of asbestos type in air samples?

Transmission Electron Microscopy (TEM) is the technique that provides a definitive identification of asbestos type in air samples due to its high resolution and ability to visualize the fine structure of particles at the nanoscale. TEM can differentiate between the various types of asbestos fibers, such as chrysotile, amosite, and crocidolite, based on their morphology and crystallography. This high-resolution imaging is essential for accurate identification because different asbestos types exhibit distinct physical characteristics and structural forms.

While other techniques such as Optical Microscopy and Phase Contrast Microscopy are useful for providing preliminary analysis of air samples and can indicate the presence of fibers, they lack the resolution and specificity needed to conclusively identify the asbestos type. Scanning Electron Microscopy (SEM) can also provide detailed images of particles, but it does not always produce the same level of definitive identification as TEM because it does not have the same capability to evaluate and differentiate the crystallographic structures of the fibers. Therefore, TEM stands out as the definitive method for asbestos type identification in air samples.