Table 2. Efficiency of the test mask without Micro Ventilator for filtration of Staphylococcus aureus and bacteriophage ΦΧ174.

Replicate	% Filtration assessed by infectivity
	Staphylococcus aureus	Bacteriophage ΦΧ174
Replicate 1	>99.9%	99.6%
Replicate 2	>99.9%	99.8%
Replicate 3	99.7%	>99.9%
Replicate 4	99.8%	99.8%
Replicate 5	>99.9%	99.5%
Mean ± SD (N=5 replicates)	99.8%±0.1%*	99.7%±0.2%*

This work was performed by Nelson Laboratories (Salt Lake City, USA). *, For the purpose of averaging and statistical analysis, values indicated as >99.9% were treated as 99.9%. SD, standard deviation.