There are no data on airborne concentrations or the health effects associated with different levels of exposure. There are no occupational exposure limits for biological organisms. A process has been developed for selecting respirators to control exposures to infectious aerosols. The traditional industrial hygiene respirator selection method has served as the basis for this proposal with suggestions for modifications when data on occupational exposure limits, toxicity, concentrations, etc. are lacking. The modifications include methods for ranking toxicity using infectious dose and measures of disease severity, as well as methods for ranking concentrations using knowledge of room volume, uncontaminated air flow, and source.
Source is ranked by activity or procedure.
The APF is then adjusted for special use considerations. Two case studies are presented to illustrate the proposed decision logic. For each situation, the procedure yielded choices which were both protective and reasonable. These results suggest that the procedure will be applicable to a variety of settings for a range of infectious organisms. Aerosol Filtration Characteristics of Air-Purifying Escape Mask.