This is an early prototype of a two layer cloth mask made by my sister. The final mask will reposition the straps and have a twist tie sewn in above the nose bridge to get a better fit. I will be offering support for her to make masks to prolong the life of N-95 respirators, and to help protect others from people who do not know they have symptoms. The newer mask is an updated version of the Olson Mask
The fabrics used in a mask as well as the mask air leakage affect the ability of the cloth mask to filter out large and small particles. Combining multiple layers of different fabrics improves the mask filter efficiency. ACS Nano April, 2020.
MDH (Minnesota Department of Health (interim guidelines on alternative face masks) Wash dirty masks between each use. Wash in hot water with regular detergent. Dry completely on hot
setting. It contains guidance for when the respirators are appropriate to use and several websites with suggested designs.
The University of Minnesota has a MN COVID Mask Sewist Group. You participate by making masks or requesting a cloth mask. It also has a Face covering FAQ on the requirement that all people on campus are required to wear face coverings. Please also see the UHS guide for fabric face coverings.
Research paper (NIH) that does a comparison of cloth mask materials - Testing the efficacy of home made masks. It is interesting that the results of this study is slightly different from my current limited tests of recent home made mask designs.
Lisa Brosseau offers a commentary that masks for all is not based on sound science. Filter efficiency and fit are key to the effectiveness of respirators. The filtering efficiency and face fit of the cloth mask is variable and deficient when compared to a properly fitted N-95 respirator.
A recent summary at Fast.ai suggests that combining social distancing with cloth mask usage appears to be helpful in flattening the curve in some countries notably the Czech Republic. The video below explains how the Czech republic successfully established their Masks4All program using the phrase, "I protect you. You protect me."
Home Made Face Mask Use - Czech Republic
The calls for general public mask use are increasing. In Australia grocery shoppers must wear masks - Reuters. The CDC has issued guidelines on the voluntary use of cloth face coverings. They emphasize the use of these cloth face coverings is an addition the maintenance of social distances and proper hand hygiene.
Amy L. Baxter, MD in a Medscape article asks Is it Time that We All Start Wearing Face Masks?
She offers strong arguments that it will reduce the efficiency of transmission from an infected individual to another person.
My comments:
The cotton masks do not work as well as a properly fitted and worn N-95 respirator. However a multi-ply cloth respirator covering the mouth and nose will limit the amount of droplet aerosols produced during coughing, speaking, sneezing, or singing. Wearing a cloth mask will reduce a person's ability to infect another person. It will also make it more difficult for a person to directly touch their nose or mouth.
Breathing through a mask can cause more resistance from breathing. If you have questions about the use of one of these masks consult with your super busy health care provider.
Hand hygiene after mask removal is important. These masks will need to be washed and dried daily in a dryer on high temperature setting. Others have recommended washing, drying, and steam ironing for additional disinfection.
Maybe this will be another way we can all do our part to flatten the curve.
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