What are the two methods of bulk sampling for asbestos?

The two primary methods of bulk sampling for asbestos are Polarized Light Microscopy (PLM) and Transmission Electron Microscopy (TEM). PLM is widely used for the identification of asbestos fibers in bulk materials because it allows for the identification of different types of asbestos based on their optical properties. It is effective for samples such as floor tiles, insulation, and roofing materials.

TEM, on the other hand, is a more advanced technique that provides a higher resolution and can identify asbestos at a much smaller scale, making it useful for confirming the presence of asbestos fibers that may not have been detected by PLM. Using TEM can also provide detailed information about the size and shape of the fibers, which is crucial in risk assessment and management strategies.

While PLM and TEM complement each other, they serve different purposes within asbestos analysis. This makes them the correct pair of methods for bulk sampling, essential for determining asbestos content in various materials. Other options mentioned do not represent recognized methods used for bulk sampling, which reinforces why PLM and TEM are the appropriate response.