If you’re counting on a cloth mask to protect you from COVID-19, you may need to re-think that strategy, a new study shows.
Researchers found that cloth face masks do little to fend off tiny airborne particles while concluding that specialized N95 and similar masks do a much better job.
“Masks are air filters, and woven fabrics, such as cotton, make for good jeans, shirts, and other apparel, but they are lousy air filters,” says study co-author Richard Sear. “So, use woven fabric for clothing, and N95s, FFP2s or KF94s for masks,” adds Sear, of the University of Surrey in England.
Filtering out airborne particles
COVID-19 is transmitted primarily via airborne particles. An infected person breathes out virus-carrying particles that can be inhaled by another person, causing them to become infected.
That’s why masks are widely considered an important first-line defense against airborne transmission of the disease, but, as research is increasingly showing, not all masks provide equal levels of protection.
In this study, published March 1 in the journal Physics of Fluids, researchers compared woven fabric masks with N95 masks and similar face coverings. They looked to see how effective they are at filtering out particles a micrometer and larger in diameter.
Airflow simulations showed that when breathing through cloth, most of the air flows through the gaps between the fibers in cloth masks, bringing with it more than 90% of the particles.
“In other words, these relatively large gaps are responsible for cloth being