Table 1.
Average viral filtration efficiency (VFE) of different types of fabric masks compared with N95, surgical, and disposable masks determined using ASTM F2101-14 standard method with bacteriophage MS2 as the challenge virus.
| Mask | Average Viral Filtration Efficiency for an Average Aerosol Size of 6.0 µm (VFE(6.0 µm)) (%) [Range] |
Average Viral Filtration Efficiency Calculated with the Larger Aerosols Excluded to Give an Average Aerosol Size of 2.6 µm (VFE(2.6 µm)) (%) [Range] |
Description 1 |
|---|---|---|---|
| N95 | 99.9 [99.8–100] |
99.3 [98.6–99.7] |
KN95 (nonmedical device GB2626-2006) |
| Surgical 1 | 99.9 [99.8–100] |
99.5 [98.7–99.5} |
Level 1 single use surgical mask (according to AS 4381:2015 Nelson Laboratories, USA, bacterial filtration efficacy (BF) average 98.2%, minimum 97.1% as per ASTMF1862) |
| Surgical 2 | 99.6 [99.3–99.8] |
98.5 [98.3–98.6] |
Surgical face mask (99.9% BFE 2) |
| Disposable 1 | 99.9 [99.9–100] |
99.7 [99.7–99.9] |
Disposable face mask (nonmedical GB/T32610-2016) |
| Fabric 1 | 54.4 [54.3–54.6] |
65.8 [64.1–67.6] |
Three layered masks made of 100% cotton |
| Fabric 2 | 67.3 [54.8–92.1] |
90.9 [86.5–94.3] |
Denim face mask—double layer stretchy cotton |
| Fabric 3 | 93.6 [92.1–96.3] |
89.0 [86.1–90.5] |
100% hemp outer layer, poly membrane mid layer, and organic cheesecloth inner layer |
| Fabric 4 | 50.3 [49.7–51.2] |
63.6 [51.8–75.0] |
Two layers of 100% Mulberry Silk |
| Fabric 5 | 54.9 [55.4–55.7] |
93.32 [86.9–97.7] |
Washable fabric face mask with pocket for filter made from cotton and poplin fabric |
| Fabric 5 + dried baby wipe | 98.5 [97.7–99.6] |
97.6 [97.0–98.5] |
Fabric 5 with a dried baby wipe inserted into the pocket |
| Fabric 5 + vacuum cleaner bag | 99.5 [98.9–99.9] |
98.8 [96.9–99.8] |
Fabric 5 with a section of a vacuum cleaner bag inserted into the pocket |
| Fabric 6 | 98.6 [97.7–99.6] |
99.1 [98.3–99.7] |
Made using the Victorian DHHS design [13]. Two layers of reusable shopping bag (nonwoven polypropylene) and one layer of cotton |
All masks were tested in triplicate except Fabric 1, which was tested in duplicate. The average aerosol size that the masks were tested against was 6.0 µm and the viral filtration efficiency was calculated using this aerosol size and then again with the larger aerosol excluded to give an average aerosol size of 2.6 µm to better represent the size of aerosols that reach the lower respiratory system. 1 Description information was collected from the mask packaging or seller website. 2 Bacterial filtration efficiency.