TABLE I.
Mask measurements and 2–16 kHz acoustic attenuation results (mean ± standard deviation).
| Material | Layers | Thickness (mm) | Mass (g) | Speaker atten. at listener (dB) | Human atten. at listener (dB) | Human atten. at lapel (dB) | |
|---|---|---|---|---|---|---|---|
| 1 | Polypropylene (YY/T 0969) | 3 | 0.4 | 3 | 3.6 | 2.8 ± 1.3 | 1.0 ± 1.4 |
| 2 | KN95 respirator (GB 2626) | 2 | 0.6 | 4 | 4.0 | 2.6 ± 1.1 | 0.0 ± 1.3 |
| 3 | N95 respirator (3 M 8210) | 1 | 1.5 | 9 | 5.7 | 5.4 ± 1.2 | 3.6 ± 1.3 |
| 4 | Cotton jersey (generic) | 2 | 0.7 | 11 | 4.0 | 3.1 ± 1.1 | 0.5 ± 1.1 |
| 5 | Cotton plain (handmade) | 2 | 0.5 | 11 | 4.0 | 4.3 ± 1.1 | 1.4 ± 1.2 |
| 6 | Cotton/spandex jersey (generic) | 3 | 1.5 | 16 | 6.1 | 5.2 ± 1.5 | 2.3 ± 1.3 |
| 7 | Cotton/spandex jersey (LASC) | 2 | 0.9 | 17 | 8.2 | 6.1 ± 1.2 | 2.0 ± 1.1 |
| 8 | Cotton plain and denim (Jo-Ann) | 2 | 1.1 | 21 | 9.4 | 10.0 ± 1.3 | 3.2 ± 1.1 |
| 9 | Cotton percale bedsheet and polyester trim (handmade) | 2 | 1.0 | 14 | 12.6 | 9.5 ± 1.7 | 3.1 ± 1.3 |
| 10 | Cloth and vinyl window (handmade) | 1 | 0.4 | 12 | 10.8 | 7.8 ± 1.2 | --2.0 ± 1.5 |
| 11 | Cloth and PVC window (UTSDesignStore) | 1 | 0.3 | 7 | 12.5 | 8.0 ± 1.7 | 0.4 ± 1.6 |
| 12 | Plastic shield (generic) | 1 | 0.4 | 50 | 13.7 | 8.2 ± 1.2 | --7.6 ± 1.3 |