DS Consulting, Inc. is a participant in the Industrial Hygiene Proficiency Analytical Testing (IHPAT) program with laboratory ID No. 188987. Our Air Monitoring Specialists all have NIOSH 528 equivilant certifications to analyze for airborne asbestos fibers via PCM, allowing us offer on-site, or off-site, PCM analysis for asbestos projects.
Phase contrast microscopy (PCM) analysis (NIOSH method 7400) is a technique used for determinations of airborne asbestos fibers. An air sample for PCM analysis is collected on a filter medium which is dissolved during sample preparation so that the collected particulate can than be viewed under the microscope.
Phase contrast microscopy is often used for analysis of samples for airborne asbestos fibers. The sample is collected on a mixed cellulose ester membrane (MCEM) filter with a 0.8 mm (micron) pore size. MCEM filter is then cleared with a chemical solution and the collected fibers are counted under the 400X magnification. All fibers longer than 5 mm, wider than 0.25 mm and of aspect ratio of 3:1 or greater are enumerated. The airborne fiber concentration is obtained from the microscopic count and air sampling data.
The PCM analysis is fast and inexpensive and DS Consulting, Inc. can performed this on site during asbestos removal operations for fast turnaround. Inability to distinguish between the asbestos and non-asbestos fibers is the main disadvantage of PCM. Therefore all fibers that meet the counting criteria are counted as asbestos fibers. Where precise determining of airborne asbestos fibers is needed transmission electron microscopy (TEM) should be used. Air sampling for the determination of airborne asbestos and phase contrast microscopy analysis is fully described in the NIOSH analytical method 7400.