With several masks being made by clothing firms instead of highly controlled manufacturers in the medical industry, how would we know definitively how well the mask works?

To look at these issues, experts have shifted focus from their typical ventures. The responses they discovered are both more straightforward and more complex than we would assume.

First, to understand what allows a mask to work, it's necessary to know what it's meant to do physically. The fundamentals are all known: masks prevent viruses from penetrating the mouth and nose and spreading into the air.

The effectiveness of different masks, particularly to the user and how much virus could penetrate in a mask, was studied by Northeastern researchers Loretta Fernandez and Amy Mueller.


The more durable they are, the more effective mask is when it falls to cloth facemasks. Many cloth facemasks arrive with filters, which are an extra security layer.

"Masks don't really act as a sieve," Fernandez explains. "We're not asking them to be like a strainer." Instead, airflow needs to be slowed down by the masks.

"If the air paths [into the mask] can be made to have twists and turns, that increases the chance of particles coming into contact with the fibers in the mask, [where they'll] stick and get trapped," Fernandez added.

Thus why additional fabric layers generally make masks more effective. Extra layers indicate that air must pass via more complex pathways, and virus particles are more likely to be trapped in the mask's fibers rather than touching the mouth and nose of the person.


Your mask's fabric should not be the only element that influences its effectiveness; fit is just as critical, if not more so.

"We found that the variation was often more related to the seal of the mask, rather than the material itself. A huge fraction of the base efficacy of any mask comes from having a good seal around it. Within the range above that efficacy, different materials have different properties, but we found that a very wide range of materials could achieve a decent level of filtration," Mueller explains.

Having a facemask, which fits above your nose, including above your chin, is necessary. To guarantee a close fit, the safest masks are the versions with a piece of wire on the nose. You wouldn't want a mask that is too loose: if you notice your breath flowing out on your cheeks, you could tighten a knot around your ears, while a tight-fitting mask can redirect your air into your face or your chest.


To figure out just how successful it is in actively diverting your breath, one very effective way to test a face mask is to literally light a match and then attempt to puff out the match through the face mask.

The flame could not even be moved by a decent facemask. For instance, one that isn't really efficient, a poorly constructed fabric one, will let you puff the flame out very quickly.