Fiber counts are performed using Phase Contrast Microscopy (PCM). This method is used primarily for estimating fiber concentration, but it does not differentiate between asbestos and other fibers. This test can be used in conjunction with electron microscopy if fiber differentiation is necessary.  Our PCM Laboratory is equipped to quantify airborne fibers collected by high or low volume air-monitoring using PCM cassettes.  Within the PCM cassettes are PCM filters through which the sample air is pulled.  The air passes through but the small pore size of the filter matrix prevents fibers of a size larger than the pores from escaping the cassette.  This PCM filter is removed, prepared, and mounted on a glass slide.  Our technicians use Phase Contrast Microscopes to determine the fiber count in the samples provided.  Eight (8) hour Time Weighted Averages can be calculated upon request.