Facts About Masks: Which Material?
If one considers the elemental purpose of a mask, it’s to provide a barrier to reduce the spread of exhaled, potentially virus-containing, droplets. Many opinions on social media cover the size of the viruses, droplets, and the fabric density of masks. I’m not going to do that because it’s the wrong argument. Instead, I’m going to review studies that have examined the potential blocking ability of various types of manufactured and home-made masks.
In a study published in 2013, researchers tested different masks in a series of experiments using a bacteria and a virus. The surgical mask was by far the best choice blocking up to 90% of the virus with the least drop in breathability. Home-made cloth masks made up of single layer of cotton blend were 70% effective against viral transmission.
In a study published in April of this year, researchers tested a variety of masks for blocking ability of an avian flu virus. The N95 mask was best at 99.98%, the surgical mask was second with 97.14%, and a double-layer cloth mask was 95.15%.
In a study that’s currently in the peer-review process, researchers tested 10 different fabrics compared to the typical surgical mask for blockage and breathability. The surgical mask blocked 96.3% with the best breathability. Single-layer, cotton and polyester blend fabrics blocked 90.1% with a comparable breathability (in the photo above, my mask is the least effective). A used dish-cloth blocked 97.9% with acceptable breathability. They also found that doubling and tripling the cloth fabric increased the amounts blocked and still allowed for good breathability, so Paula and Riley are better prepared than I am.
Masks, even those made of cloth that can be found in most homes, can be effective in reducing the amount of droplets spread. What about wearing a mask during exercise? I’ll give you my results and wrap this up on Saturday.
What are you prepared to do today?
Dr. Chet
References:
1. Disaster Med Public Health Preparedness. 2013;7:413-418.
2. DOI: 10.1002/jmv.25805.
3. https://www.medrxiv.org/content/10.1101/2020.04.19.20071779v1.full.pdf
Info on Our Masks
• Riley’s mask is available from Cincinnati Zoo in several breeds (he chose the hippo); proceeds help support the zoo
• Paula’s mask is made by Humans In Action, which provides work for displaced garment workers in Guatemala; many colors available with ties instead of earloops
• Dr. Chet’s mask is from Sports Fan Island, which also sells other types of face masks for sports fans
