Asbestos is a group of naturally occurring fibrous silicate minerals which have been used widely in construction and industry because of its flexibility, strength, chemical resistance, insulation properties and non-combustibility. Asbestos releases fibres into the air if it becomes damaged or disturbed and asbestos fibre inhalation is associated with lung diseases, i.e., asbestosis, mesothelioma and lung cancer.
Airborne asbestos fibres are sampled by drawing a measured volume of air through a membrane filter. This is then mounted onto a microscope slide and rendered transparent with solvents, generally acetone/glycerol triacetate. Fibres on a measured area of filter are counted using phase contrast microscopy (PCM) and the number concentration of fibres in the air is calculated.
Casella offers specific sampling accessories for the analysis of asbestos fibres; An open faced filter holder fitted with an electrically conducting cylindrical cowl is required along with MCE filters with a printed grid. MCE filters (a mixture of cellulose acetate and cellulose nitrate) are recommended for asbestos sampling as they are readily rendered transparent for fibre counting. Pre-loaded asbestos cassettes are also available in pore sizes of 0.8µm and 0.45µm for ease of use.