Asbestos air monitoring checks for the presence of respirable asbestos fibers in the air to assist with the assessment of exposure and the effectiveness of control measures. Respirable asbestos fibers are less than 3 μm wide and more than 5 μm long, and have a length to width ratio of more than 3:1.
Generally undertaken where asbestos containing products are in a poor condition, and potentially liberating asbestos fibres into the air, or where asbestos containing materials are being removed, asbestos air monitoring considers only respirable asbestos fibers to be a risk to human beings.
There is a presumption that all fibers observed under a phase contrast microscope that meet certain geometrical specifications are asbestos. Further testing of asbestos air monitoring may be required to confirm the chemical composition using transmission electron microscopy test equipment (TEM).