Comparisons of microorganism loading from two air filter materials during the first eight weeks of service life.

As part of an ongoing investigation on service life of air filtration material, a new type of airfiltration material (multi-layered polymer) was compared with a widely used material todetermine growth or survival of micro-organisms after normal dust loading. Blinding wasperformed by the manufacturer supplying the materials as anonymous A and B. Microorganismswere extracted after 2, 4, 6, and 8 weeks by washing (shake out) and plating thesolution onto agar media, incubated and differentiated. Vital fluorescence microscopy wasalso performed. The results showed a significant difference (P