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Specific features of PFMs used in this study.
| Property | Specifications |
|---|---|
| Appearance |  |
| Classification | Medical surgical masks |
| Standard | YY0469-2011 |
| Inner dimensions (length × width) | 17.0 cm × 9.0 cm |
| Materials/Usage | 25 g/m2 high standard filter layer + 2 nonwovens/Disposable |
| Filter classification | BFE>95%, PFE>70% |
| Size/Weight | Standard/3.0 g |
| Exhalation valve | No |
| Pressure difference | 35.5 Pa/cm2 |
| Albedo | 24% |
| Dead space volume | 90–180 mL |
