Respiratory protection provided by five new contagion masks.

The effectiveness of five recently developed contagion masks in filtering air-borne particles (1 to 5 mu diam) has been reported. One mask, available in four sizes, was 99% efficient. This mask can be reused after sterilization. The other four masks are available in only one size and are intended to be used one time only. Two of these four disposable types were more than 90% efficient but the variability of their respective test results was much greater than that for the reusable mask. The two remaining disposable types were less than 80% efficient. Two of these contagion-mask types were worn by hospital personnel for periods of up to 8 hr to determine the effect of such prolonged use on aerosol filtration efficiency. No significant decrease in filtration efficiency was noted. Physicians, nurses, and other hospital personnel who wear masks will benefit from the increased individual respiratory protection afforded by improved contagion masks. Concurrently, the incidence of hospital patient air-borne infections should be greatly reduced.