Dust Characterization incorporates physical testing with Polarized Light Microscopy (PLM), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) to identify nearly all unknown particles in dust from cotton fibers, dander and dust mites to unusual materials such as carbon black, metal oxides and minerals. This analysis is best performed in conjunction with Air-O-Cell cassettes or other media to identify any fungal allergens. This method is the perfect procedure for initial site surveys where Indoor Air Quality is in question.
Sampling of bulk materials is typically performed by the glove bag technique. Dust is commonly collected by micro-vacuuming or wipe sampling with a 4x4 inch piece of baby wipe, (no aloe or cleaners). Air sampling is performed using a 0.1m Polycarbonate filter and an Air-O-Cell cassette.
0.1m Polycarbonate filter 10-15 lpm ( volume of 1,500 – 3,000 liters )
Air-O-Cell Cassette 10-15 lpm ( volume of 75 – 200 liters)
When ``Site Standards" are taken of the various suspect materials through out the job site, the particles found in the samples can be matched to the Site Standards. This can pin point the actual source of the contamination. When air sampling for fungi, a sample should be acquired from outside the building preferably near a fresh air intake. This will act as a ``Baseline" for the fungi concentrations found in the sampling area.