Mask Ratings
Following are the ratings for different types of masks. The ratings are from work by Phillip Clapp, a research assistant professor at the University of North Carolina at Chapel Hill, and his colleagues.
Reference data for N95 masks, Surgical masks, and Shoptowel Masks.
Reference for KN95 masks
More references:
January 2021 EPA Tools and Resources Webinar: Effectiveness of Medical and Cloth Masks for COVID-19 Protection
CDC Data Tracker in Casses per 100k Poulation
The CDC link above is best viewed on a computer. The map of the United States showing cases per 100k population does not allow display of detailed state data on a cell phone. Clicking on the state using a mouse on a computer does display the detailed data.
Maps shown in media outlets often show number of cases in percentages, which is invalid since it ignores the size of the population of the state.
A group of 100,000 with 2,000 cases is a 2%.
A group of 1,000,000 with 2,000 cases is a 0.2% .
Reference data for N95 masks, Surgical masks, and Shoptowel Masks.
Reference for KN95 masks
| N95 | 2 Tie Straps | 95% |
| Jia Hu Kang KN95 | Ear Loops | 85% |
| Blue Shop Towels | 2-Layer tight fit | 75% |
| Surgical Mask | 2 Tie Straps | 70% |
| Guangdong Fei Fan KN95 | Ear Loops | 53% |
| Blue Shop Towels | 1-Layer tight fit | 50% |
| Surgical Mask | Ear Loops | 40% |
| Cloth Mask | Weave or Material too variable to test |
0% to 40% estimate from other sources |
More references:
January 2021 EPA Tools and Resources Webinar: Effectiveness of Medical and Cloth Masks for COVID-19 Protection
CDC Data Tracker in Casses per 100k Poulation
The CDC link above is best viewed on a computer. The map of the United States showing cases per 100k population does not allow display of detailed state data on a cell phone. Clicking on the state using a mouse on a computer does display the detailed data.
Maps shown in media outlets often show number of cases in percentages, which is invalid since it ignores the size of the population of the state.
A group of 100,000 with 2,000 cases is a 2%.
A group of 1,000,000 with 2,000 cases is a 0.2% .
Construction of Two-Layer Shop-Towel Mask
Towel material is from Scott Shop Towels Original, number 10-29-625-0-02, Distributed by Kimberly-Clark Global Sales,LLC Roswell, GA 30076-2199.
Rubber bands are size #64, 3-1/2 x 1/4 from Alliance Rubber Company,P. O. Box 20950, Hot Springs, AK 71903, sold on Amazon.com.
Rubber bands are size #64, 3-1/2 x 1/4 from Alliance Rubber Company,P. O. Box 20950, Hot Springs, AK 71903, sold on Amazon.com.
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Modification of Adult KN95 Mask To Fit Child
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