Table. Filtration Efficiency and Proportion Below 95% by Shifts Worn, Stratified by N95s Model.
| Respirator model and shifts worn | No. | Filtration efficiency | ||
|---|---|---|---|---|
| Median (IQR), % | Mean (SD), % | <95%, No. (%)a | ||
| All models | ||||
| 0 | 30 | 99.6 (99.3-99.7) | 99.5 (0.3) | 0 |
| 1 | 170 | 99.5 (99.0-99.9) | 99.2 (1.3) | 3 (1.8) |
| 2 | 89 | 98.8 (97.4-99.2) | 97.8 (2.4) | 9 (10.1) |
| 3 | 52 | 97.9 (94.0-98.8) | 96.0 (4.5) | 15 (28.8) |
| 4 | 29 | 96.9 (93.5-98.0) | 95.2 (4.3) | 10 (34.5) |
| 5 | 25 | 96.3 (92.7-97.9) | 94.2 (6.6) | 10 (40.0) |
| Respirator 1 | ||||
| 0 | 10 | 99.7 (99.6-99.7) | 99.7 (0.1) | 0 |
| 1 | 48 | 99.2 (98.9-99.5) | 99.0 (1.1) | 1 (2.1) |
| 2 | 39 | 98.9 (98.3-99.2) | 98.6 (1.0) | 1 (2.6) |
| 3 | 30 | 98.7 (97.8-99.0) | 97.6 (3.4) | 3 (10.0) |
| 4 | 16 | 97.6 (95.4-98.2) | 96.5 (2.6) | 3 (18.8) |
| 5 | 15 | 97.1 (95.3-98.2) | 96.1 (3.1) | 4 (26.7) |
| Respirator 2 | ||||
| 0 | 5 | 100.0 (100.0-100.0) | 100.0 (0) | 0 |
| 1 | 86 | 99.9 (99.7-100.0) | 99.8 (0.4) | 0 |
| 2 | 19 | 99.2 (98.9-99.8) | 98.3 (3.1) | 2 (10.5) |
| 3 | 8 | 96.5 (91.1-97.4) | 94.3 (5.1) | 3 (37.5) |
| 4 | 4 | 97.3 (96.1-97.8) | 96.5 (2.6) | 1 (25.0) |
| 5 | 2 | 96.3 (94.5-98.0) | 96.3 (5.0) | 1 (50.0) |
| Respirator 3 | ||||
| 0 | 15 | 99.3 (99.1-99.5) | 99.3 (0.2) | 0 |
| 1 | 36 | 98.6 (97.7-99.1) | 98.0 (2.0) | 2 (5.6) |
| 2 | 31 | 97.4 (95.1-99.0) | 96.7 (2.7) | 6 (19.4) |
| 3 | 14 | 93.9 (90.3-97.4) | 93.4 (4.9) | 9 (64.3) |
| 4 | 9 | 93.4 (88.2-96.9) | 92.1 (5.9) | 6 (66.7) |
| 5 | 8 | 92.4 (88.2-96.6) | 89.9 (9.9) | 5 (62.5) |
a
No. and proportion of all N95s worn for 0, 1, 2, 3, 4, and 5 shifts that had a filtration efficiency below 95%.