PERFORMANCE OF RESPIRATOR FILTERS AND SURGICAL MASKS AGAINST BACTERIAL AEROSOLS

A laboratory test system has been designed and built to measure the ef ficiency of filter material from several commonly used respirator filt er cartridges, approved disposable dust masks, nuisance dust masks, si ngle-use surgical procedure masks and a resuscitation mask against aer osols of the bacteria Bacillus subtilis subspecies globigii, Micrococc us luteus and Pseudomonas alcaligenes. All tests were carried out at a flow rate of 30 l min(-1). The same materials were also tested with m onodisperse urea aerosols in the size range 1.5-9 mu m and with the Br itish Standard BS 4400 sodium chloride aerosol, which has a mass geome tric mean diameter of 0.6 mu m and a geometric standard deviation of 2 .3. One type of surgical mask allowed penetration of up to 83% of a mi crobiological aerosol and 87% of a non-biological aerosol, and nuisanc e dust masks allowed penetrations of up to effectively 100% for a micr obiological aerosol and 91% for a non-biological aerosol. The material s of the other surgical masks and the resuscitation mask, all of which were electrically charged, performed better against all the test aero sols. Penetration of microbiological aerosols through the respirator f ilter materials was no greater than 0.88%, and penetration of non-biol ogical aerosols no greater than 1.72%. The results for microbiological aerosols generally corresponded to those for the non-biological aeros ols in the same size range. Crown Copyright (C) 1997 Published by Else vier Science Ltd.