Wearing a mask in public has become a mandate in many cities and states across the U.S. And as many craft individuals flock to Etsy to fulfill this demand, others wonder the efficacy of donning a mask to prevent infection. Recently, a company called Smart Air performed an unbiased mask fit-test study. They tested 15 different masks types on three different people, and they concluded that the classic blue surgical mask can filter out about 63% of particles ranging from 0.01-1.0 μm, while an N95 yielded 99.7% efficacy.
Keep in mind that a free coronavirus particles range in diameter from 0.06-0.14 μm. However, most often, the virus coming from an infected individual will be suspended in ‘droplets’ from saliva or lung fluids, thus the virus particle delivery vehicle is far greater than the size of a single virus.
Moreover, there is always the concept of having to account for how varying degrees of particulate velocity and pressure could greatly influence mechanism of transmission. A study done by Leonas, et. al, in 2003 considered just this. They subjected various masks types to pressure ranging from about 1.5 to 3 psi and found that mask did diminish in performance in relation to the force of particles hitting the mask, but only at the higher-pressure ranges. Considering that the average human sneeze generates about 1 psi of force, it is not likely to be a big influencing factor.
Regarding homemade cloth masks—these are more difficult to rate due to the wide range in variation based on the given material chosen to construct the mask. In this, wearing a cloth mask would more likely to protect others from encountering your contaminated droplets by containing the infectious droplets behind the mask itself versus protecting the wearer of the mask from inhaling infectious droplets.
Nonetheless, the argument has been made that wearing a mask of any kind reinforces the wearer to not touch their face as it is a route for infection. Yet given the fact that, according to the Physico-chemical aspects of Textile Coloration textbook, cotton pores often exceed 10-20 micrometers, making them too large to filter out free viral particles.
In an interview by Business Insider, Ben Cowling professor of epidemiology and mask researcher at the University of Hong Kong’s School of Public Health said, “The argument … about everybody wearing a mask is not that it will prevent everyone from getting infected — it’s that it will slow down transmission in the community a bit… That’s already useful. Just to have even a small effect is useful.”
Bottom line is that any sort of face covering is better than none if your goal is to reduce viral spread overall, and while the classic blue surgical masks do not work as well as N95 masks, they are better than cloth masks, they are cheaper and often more readily available making them a good alternative. However, if your intention is to protect yourself from viral particles, N95 masks are the superior disposable-mask of choice.
Check out this DIY mask designed by a San Antonio nurse that is rated better than an N95.
ABOUT THE AUTHOR
Alex Kirkpatrick is a doctoral student in the Molecular Immunology & Microbiology discipline of the Integrated Biomedical Sciences Ph.D. program. She is interested in host-pathogen interactions, cellular biology, microscopy, protein purification, ELISA, cell culture, immuno-techniques. Read the article Alex Kirkpatrick: Cats, Bacteria and True Crime Documentaries >>