| Flow Rate: 1.2 CFM | |||
|---|---|---|---|
| Filter Efficiency (%) | Pressure Differential | ||
| Sample/Fabric | <300 nm Average ± Error | >300 nm Average ± Error | ΔP (Pa) |
| N95 (no gap) | 85 ± 15 | 99.9 ± 0.1 | 2.2 |
| N95 (with gap) | 34 ± 15 | 12 ± 3 | 2.2 |
| Surgical mask (no gap) | 76 ± 22 | 99.6 ± 0.1 | 2.5 |
| Surgical mask (with gap) | 50 ± 7 | 44 ± 3 | 2.5 |
| Cotton quilt | 96 ± 2 | 96.1 ± 0.3 | 2.7 |
| Quilter’s cotton (80 TPI), 1 layer | 9 ± 13 | 14 ± 1 | 2.2 |
| Quilter’s cotton (80 TPI), 2 layers | 38 ± 11 | 49 ± 3 | 2.5 |
| Flannel | 57 ± 8 | 44 ± 2 | 2.2 |
| Cotton (600 TPI), 1 layer | 79 ± 23 | 98.4 ± 0.2 | 2.5 |
| Cotton (600 TPI), 2 layers | 82 ± 19 | 99.5 ± 0.1 | 2.5 |
| Chiffon, 1 layer | 67 ± 16 | 73 ± 2 | 2.7 |
| Chiffon, 2 layers | 83 ± 9 | 90 ± 1 | 3.0 |
| Natural silk, 1 layer | 54 ± 8 | 56 ± 2 | 2.5 |
| Natural silk, 2 layers | 65 ± 10 | 65 ± 2 | 2.7 |
| Natural silk, 4 layers | 86 ± 5 | 88 ± 1 | 2.7 |
| Hybrid 1: cotton/chiffon | 97 ± 2 | 99.2 ± 0.2 | 3.0 |
| Hybrid 2: cotton/silk (no gap) | 94 ± 2 | 98.5 ± 0.2 | 3.0 |
| Hybrid 2: cotton/silk (gap) | 37 ± 7 | 32 ± 3 | 3.0 |
| Hybrid 3: cotton/flannel | 95 ± 2 | 96 ± 1 | 3.0 |
The filtration efficiencies are the weighted averages for each size range—less than 300 nm and more than 300 nm.
Table reproduced from Konda A, et al. Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks. ACS Nano. 2020;14(5):6339-6347.
For additional data on mask filtration efficiency and the associated physics, see:
- Howard J, et al. An Evidence Review of Face Masks Against COVID-19. Proc Natl Acad Sci USA. Dec 2020.
- Qaseem A, et al. Use of N95, Surgical, and Cloth Masks to Prevent COVID-19 in Health Care and Community Settings: Living Practice Points From the American College of Physicians (Version 1). Ann Intern Med. Oct 2020.
- Li L, et al. Assessing the Effectiveness of Using Various Face Coverings to Mitigate the Transport of Airborne Particles Produced by Coughing Indoors. Aerosol Sci Technol. Nov 2020.
- Clapp PW, et al. Evaluation of Cloth Masks and Modified Procedure Masks as Personal Protective Equipment for the Public During the COVID-19 Pandemic. JAMA Intern Med. Dec 2020.
- Ueki H, et al. Effectiveness of Face Masks in Preventing Airborne Transmission of SARS-CoV-2. mSphere. Oct 2020
- Akhtar J, et al. Can Face Masks Offer Protection from Airborne Sneeze and Cough Droplets in Close-Up, Face-to-Face Human Interactions?—A Quantitative Study. Phys Fluids. Dec 2020.
- Xi J, et al. Effects of Mask-Wearing on the Inhalability and Deposition of Airborne SARS-CoV-2 Aerosols in Human Upper Airway. Phys Fluids. Nov 2020.
- Kumar S, et al. The Perspective of Fluid Flow Behavior of Respiratory Droplets and Aerosols through the Facemasks in Context of SARS-CoV-2 Featured. Phys Fluids. Oct 2020.