Table 1 Aerosol particle size distribution obtained using S. epidermidis.

From: Staphylococcus epidermidis is a safer surrogate of Staphylococcus aureus in testing bacterial filtration efficiency of face masks

Stage

50% effective cut-off diameter (µm)

CFU

1

7.0

187 ± 67

2

4.7

198 ± 55

3*

3.3

607* ± 227

4*

2.1

579* ± 182

5*

1.1

824* ± 314

6*

0.65

12* ± 13

Total CFU

2.41 × 103 ± 0.69 × 103

MPS (µm)

2.71 ± 0.16

  1. Mean values over twelve positive controls, performed in different experimental tests, are presented with their standard deviations. CFUs are listed together with total CFUs and MPS values.
  2. *From 3rd to 6th impactor stages, CFUs have been enumerated by means of the “positive hole” correction.
Back to article page