• N95 masks and KN95 masks are among the best face masks you can use for COVID-19 protection, but there’s a popular version of both types of masks that you should stop using immediately.
  • The CDC says that we all wear face masks right now to help stop the spread of the novel coronavirus, but a face mask with a valve does not do a good job of protecting people in your vicinity if you’re infected.
  • Asymptomatic and presymptomatic carriers have been proven to be spreaders of the novel coronavirus, so if you have COVID-19 and you wear a mask with a valve, you might be spreading the disease without even knowing it.
  • One doctor recently wrote an essay that urges people to stop wearing N95 and KN95 face masks with valves — even a simple 50¢ 3-ply coronavirus face mask offers better protection to people around you.

Visit the CDC’s special webpage that discusses how to protect yourself from the novel coronavirus that’s flaring up yet around all across the country and you’ll see three important recommendations near the top of the page. First, you need to “wash your hands often” with soap for at least 20 seconds or with strong hand sanitizer like Purell (which is actually in stock right now on Amazon, by the way). Second, you should “avoid close contact” with people and stay at least 6 feet away from anyone while you’re outside your home. If you’re smart, you’ll keep even more distance between yourself and anyone else. And third, you need to “cover your mouth and nose with a cloth face cover when around others.”

The last piece of advice from the CDC is crucial for two reasons. First, wearing a face covering like these best-selling 50¢ face masks or a KN95 face mask helps protect you from breathing in any aerosolized virus that travels around in microscopic droplets in the air when infected people cough, sneeze, or even just breathe or speak loudly. Second, if you happen to already be infected with COVID-19, wearing a mask helps prevent you from spreading the potentially deadly virus to others. Remember, as many as half of all novel coronavirus cases may be asymptomatic, and you can also be a presymptomatic spreader for as long as 14 days after becoming infected with the virus. In either of those cases, it means you might have COVID-19 and not even know it. The key takeaway here is that wearing a face mask is absolutely crucial anytime you leave your home — but there’s actually one type of popular face mask you should never wear.

As we mentioned above, you can get a face mask that does the trick for as little as 50¢. As long as you practice strict social distancing and good hygiene, these masks are more than good enough and that’s why you see so many people out there wearing them.

Of course, there are some high-risk situations where people want a little extra protection. For example, if you have to take public transportation somewhere, if you have to fly on an airplane, or if you have to visit a doctor’s office or hospital, you definitely want to use a mask that blocks even more microscopic particles. You should never buy any N95 masks since those should be reserved for healthcare workers, and that’s why so many people buy KN95 masks instead.

High-quality KN95 masks work just as well as N95 masks, with each type blocking out at least 95% of tiny germs and organisms like viruses. But when it comes to N95 or KN95 face masks, there are two main different types. One type of mask is made entirely of fabric while the other has a plastic valve like the one seen in the image at the top of this article. This is important to note because you should never buy a face mask with a valve.

You’ve probably seen these masks all over the place, and they’re just as effective as face masks without the valve when it comes to protecting you. The plastic piece there is a one-way valve that lets air you exhale out but blocks any air from getting in. Of course, that right there is the problem: Masks with valves are nowhere near as effective at filter the air you exhale.

As Dr. Nancy A. Anoruo points out in an essay penned for ABC News, it’s crucial that people stop using masks with valves. Remember, one reason to wear a mask is to protect yourself from the novel coronavirus, but the other reason is to protect others. If you are infected — knowingly or unknowingly — using a face mask with a valve means much of the air you exhale with each word you speak, each cough, or even each breath, is unfiltered. Micro-droplets with live coronavirus can escape more easily as a result, and you’re much more likely to spread COVID-19 to others.

Face masks with valves are great for certain scenarios. If you’re working around hazardous fumes, for example, you can exhale more freely and reduce moisture and carbon dioxide buildup in the mask. But in the context of the novel coronavirus pandemic, exhaling more freely means potentially spreading the virus more freely. Masks without a valve might not be quite as comfortable since they allow more carbon dioxide to build up, but no one should be complaining about a little discomfort if it potentially means slowing the spread of the virus.

Zach Epstein has worked in and around ICT for more than 15 years, first in marketing and business development with two private telcos, then as a writer and editor covering business news, consumer electronics and telecommunications. Zach’s work has been quoted by countless top news publications in the US and around the world. He was also recently named one of the world's top-10 “power mobile influencers” by Forbes, as well as one of Inc. Magazine's top-30 Internet of Things experts.