The Conversation has been covering the science of masks since the beginning of the pandemic. Masking may no longer be required on mass transit, but you can always choose to still wear a mask. For those worried about being exposed to SARS-CoV-2 or developing COVID-19, below are highlights from four articles exploring the benefits of wearing a mask and how to get the most protection from wearing one.
1. Masks can protect the person wearing them
A lot of the reason for wearing a mask is to protect others. But early on in the pandemic, Monica Gandhi, a professor of medicine at the University of California, San Francisco, explained how masks can protect the wearer, too.
Though it’s only one of many factors, “the amount of virus that you’re exposed to – called the viral inoculum, or dose – has a lot to do with how sick you get. If the exposure dose is very high, the immune response can become overwhelmed,” explains Gandhi. “On the other hand, if the initial dose of the virus is small, the immune system is able to contain the virus.”
The better the mask, the lower the exposure dose. And in the many months since Gandhi wrote that story, a lot of work has been done to determine which kinds of masks are most effective.
2. What makes for a good mask?
The first thing to consider when wearing a mask is whether it’s a good one. Christian L'Orange is a professor of mechanical engineering and has been testing different masks for the state of Colorado since the pandemic started. He explains that there are two things that make for a protective mask. “First, there’s the ability of the material to capture particles. The second factor is the fraction of inhaled or exhaled air leaking out from around the mask – essentially, how well a mask fits.”
When it comes to these two attributes, L'Orange says, “the N95 and KN95 masks are the best option.” This performance has a lot to do with the materials they are made from. “These fibers are very tightly packed together so the gaps a particle must navigate through are very small. This results in a high probability that particles will end up touching and sticking to a fiber as they pass through a mask. These polypropylene materials also often have a static charge that can help attract and catch particles.”
Fit is the second important factor for a mask. As L'Orange writes, “a mask can offer protection only if it doesn’t leak.” N95s and KN95s are stiff and seal much better than other masks.
If you don’t have access to an N95 or KN95, surgical masks should be your second choice. They are made of densely woven material, but they don’t seal perfectly. Cloth masks should be your last choice because of their generally loose weave and bad fit. But there are ways to improve the performance of surgical and cloth masks.
There are two ways to improve the fit and performance of surgical and cloth masks. The first, explains Schiffres, is simply wearing two masks. “Double-masking is wearing a cotton mask over a medical-procedure mask.” This can greatly improve the fit and add a little bit more filtration. The second approach is to knot and tuck a surgical mask so that it fits better.
Knotting and tucking a surgical mask can make it fit much better.
Case numbers are low for now, and therefore so is the risk of catching or transmitting the coronavirus. But it is not zero; some places have higher risk than others, and new variants can come on quickly. As the team writes, all new variants that spread widely – so-called variants of concern – are likely to be highly transmissible.
The person next to you on the plane might not be wearing a mask and, as it stands, that is their choice to make. If you want to lower your own chances of catching or spreading the coronavirus, there are still a number of reasons to wear a well-fitting, high-quality mask.
Editor’s note: This story is a roundup of articles from The Conversation’s archives.