I SWAPPED OUT MY SURGICAL MASK for the N95 and KN94 ones. Given my newer masks are not inexpensive, how long can I wear one of them? One day or one week?

Today we explore the emerging science about optimal masking and the differences between N95, KN95, and KF94 masks. We’ll then pivot to how you can clean your mask before ending with a look at some ways you can reduce your chances of buying a counterfeit mask.

Covid: Why N95-type masks? Guidance is changing.

With the rise of the Omicron variant of the novel coronavirus, should you reconsider the type of mask you use? If you wear a cloth mask, the answer is yes. Listen to CNN Medical Analyst Dr. Leana Wen:

“Cloth masks are little more than facial decorations. There’s no place for them in light of Omicron.”

What’s the alternative? In light of Omicron, you should be eating at least a three-ply surgical mask. If you want to put a cloth mask over that, fine, but you should ditch the cloth mask only approach.

We need to be wearing at least a three-ply surgical mask,” she adds, which is also known as a disposable mask that you can find at most drugstores and some grocery and retail stores. “You can wear a cloth mask on top of that, but do not just wear a cloth mask alone.”

Here is how I play it — If I am in a crowded area (such as a supermarket), my go-to mask is a K95 or N95 type. These masks have a better fit, and certain substances — such as polypropylene fibers — act as mechanical and electrostatic barriers.

In practical terms, this means that these types of masks better prevent tiny particles from getting in your mouth or nose. The caveat is that they must be well-fitted to your face to work properly. If your glasses are fogging, that mask is ill-fitting.

When properly fit, N95 respirators approved by the US National Institute for Occupational Safety & Health can filter up to 95 percent of particles in the air, according to the US Centers for Disease Control.

On the other hand, surgical or disposable masks are around five to ten percent less effective than N95 respirators, depending on their ASTM International categorization — with types 1, 2, and 3 ranking just surgical masks from least to most effective.

Compared with cloth masks, well-fitted N95s do a better job of preventing very small particles from getting into your mouth or nose. Some materials — including polypropylene fibers — act as mechanical and electrostatic barriers to shared air.

Covid masks — N95 or KN95

What’s the difference between N95 and KN95 masks? It’s the place of certification. The United States certifies N95 masks, whereas China approves KN95s.

But please be careful: Approximately 60 percent of KN95 respirators sold in the United States are counterfeit and do not meet the National Institute for Occupational Health & Safety standards, according to the US Centers for Disease Control and Prevention.

KF94s have cleared Korea’s standards and appear to have a much lower probability of being counterfeit than masks from China.

Project N95, the National Clearinghouse is a reputable source for N95 and KN95 masks. Here are some clues that your mask may be a fake:Is your mask real or fake? CDC issues warnings on counterfeit N95, KN95 masksAs the Centers for Disease Control and Prevention (CDC) is considering updating its mask guidance due to the spread of…www.msn.com

Covid masks — when not to re-use

First, some basics — try not to touch the front outer part of the mask when putting it on. Use the edges and straps, if you are able. Try hard not to touch the area in front of where you breathe.

You can re-use a mask, even after being in a crowded area such as an airplane. On the other hand, if you come into the vicinity of someone with Covid (say, your co-worker tests positive), I’d toss the mask.

If it becomes visibly damaged or soiled, I would also throw away my mask.

Covid masks: Sanitizing

Naturally, if you frequently wear an N95-type mask, the more contaminated it can become. Fortunately, particles die off over hours (especially if you put the face-covering in the sun).

Here is what you should not do: Don’t wash your N95 mask. These masks have a unique static change that facilitates the filtration of viruses, and water will take away the charge.

Fortunately, the contamination risk for reusing N95 masks far outweighs the benefits of using this mask form. But did you know that you can sanitize a mask using a brown paper bag?

Here’s Dr. Joe Gastaldo, Infectious Disease Expert at OhioHealth: “The concern about wearing a mask in public if you get particles on it, perhaps even the virus, but if you store it in a dry bag, you are essentially sanitizing again over some time.”

Adds Dr. Gastaldo: “It is not the bag that’s doing the magic, it’s the process of keeping the mask away from contaminating someone else or a surface, and also keeping a dry environment for the virus to not spread or stay on the mask.”

For non-healthcare workers, consider storing your mask in a paper bag for 24 to 48 hours in a dry place. Here’s a video illustrating the process:Yes, you can clean and reuse your KN95 or N95 mask using a brown paper bagExperts say this is not recommended for health care workers, but it can help extend the life of a mask. COLUMBUS, Ohio …www.10tv.com

We change masks more frequently in my hospital and other medical settings to avoid cross-contamination. This problem is less of an issue for those in the general public.

Covid masks: My take

I try to use the highest quality mask available to me. That means I do not wear cloth masks. I choose a paper surgical mask if I don’t have an N95-type mask (or its equivalent).