Face Coverings: Not All Masks are Created Equal
At the start of the pandemic, concerns over proximity-based transmission pathways, especially via hand-to-face contact, prompted a plethora of public health guidance emphasizing the importance of routine hygiene practices like regular surface cleaning and thorough hand washing.
As the virus continued to spread, evidence emerged showing airborne transmission via respiratory droplets and fine-particle aerosols to be a highly significant infection pathway, making inhalation protection an important factor in slowing the transmission of COVID‐19.
I’m thrilled to see that public health bodies like the WHO and CDC are advocating mask wearing. But they have been slow to offer sufficient guidance regarding the efficacy of different types of masks: between the very limited protection offered by cloth face coverings and the superior protection delivered by N95s and KN95s which, when correctly fitted, filter 95 percent of aerosol particulates.
The right mask could help prevent us not only from contracting COVID-19 ourselves but also from passing it on to others, even if we’ve been vaccinated. If you want to protect yourself and others, a cloth face covering simply isn’t enough.
At the start of the pandemic, public health officials widely discouraged the general public from purchasing certain masks like N95s, in an attempt to ensure that those who needed it most — healthcare workers and others with the highest levels of exposure risk — would be able to have access to masks that were in seriously short supply. But, one of the unfortunate consequences of that message was that even when quality masks like KN95s became more widely available, many in the general public didn’t understand the importance of making the upgrade.
Thankfully KN95s are now in greater supply in many parts of the world, though I can’t credibly speak to their availability worldwide. But regardless of where you live everyone should have access to accurate information on how they can best protect themselves and others from the risk of infection — across a range of situations.
Prof. Joseph Allen from the Harvard T.H. Chan School of Public Health recommends matching your mask to your risk profile, using an N95 mask (or double-masking with surgical and cloth coverings) whenever you’re in close proximity to other people indoors, while opting for a versatile two- or three-layer mask for solo outdoor exercise.
It’s an approach I certainly favor. If I’m planning to spend time indoors — in a grocery store or a pharmacy, for example — I’ll definitely don a KN95. But if I’m heading outside for a hike, where it’s unlikely that I’ll come within 15ft of anyone else, I’ll wear a cloth or simple surgical mask, more as a social statement than a safety precaution.
Modeling responsible mask wearing is an important consideration when political and social pressure is being leveled on people who want to wear masks and who are being teased and, in some cases, intimidated for putting their safety, and that of others, first. We are all deeply influenced by social norms; wearing a mask is a good way for us all to signal our acceptance of the practice and to collectively encourage others to do the same.
I’ve been shocked by how uneven the pattern of mask wearing is across the country and around the world. We don’t yet know everything there is to know about COVID-19. But we do know that, like other respiratory infections, it can be spread by droplets and by small particles (<5µm) that can carry respirable pathogens over greater distances. We also know that airborne virus transmission can be reduced by deploying effective face masks.
Breathing and talking at normal levels generates particles (potentially containing COVID-19 pathogens) circa 1µm in size; and KN95 masks effectively filter particle sizes as low as 0.1µm to 0.3µm. Research has shown that surgical masks and unvented KN95 respirators also reduce outward particle emission rates by as much as 90 percent (compared to wearing no mask).
At home, we always keep KN95s close to hand and I recommend them to everyone I know. Not only did Marisa and I supply KN95s to our wedding guests (a very small and well-ventilated affair) but I’ve Fedexed boxes of them to friends and colleagues just to make sure they aren’t relying on inadequate cloth coverings in situations — like in hospitals — where there’s a high risk of exposure to the virus.
KN95s are not cheap, especially if you follow the guidance to wear them just one time. Less expensive masks, like reusable masks with filters or surgical masks, though not as effective as KN95s, provide far greater protection than a simple cloth face covering. It is unacceptable that essential workers of all kinds do not have universal access to adequate face masks, unless supplied by their employers. It is equally inexcusable quality masks are less accessible or attainable in low-income communities.
Thankfully, the new American Rescue Plan does provide for some additional resources in the U.S., but here and around the world, many people still feel that high-performance masks are a luxury they can’t afford. Yet masks are one of the most inexpensive ways to slow the transmission of COVID-19. To local state and national governments: can you afford not to be providing quality masks to your citizens? And to those elected and appointed officials who are actively discouraging mask wearing in general: shame on you.
It’s important to continue to see masks as part of a broader package of preventative measures, to be used in concert with good ventilation, hand hygiene, physical distancing and regular cleaning and disinfection. The rollout of mass vaccination programs in countries across the globe is bringing the hope of long-term recovery closer but the hygiene protocols we’ve adopted will be essential for a while yet and will continue to serve us, especially during cold and flu seasons to come.
Crucially, researchers believe that more widespread adoption of mask wearing could dramatically reduce the number and outcomes of COVID-19 infections — that’s a potentially huge benefit for a small act of courtesy and collective goodwill. So put your mask on, wear it properly and consider an upgrade.
Rachel Hodgdon is President and CEO of the International WELL Building Institute (IWBI), a public benefit corporation and the world’s leading organization focused on deploying people first places to advance a global culture of health.
