How Long Can You Use A KN95 Mask? Guidelines & Considerations

How Long Can You Use A KN95 Mask_

Since the Coronavirus pandemic, the demand for high-quality masks has risen across the world. Even in 2024, many healthcare settings still require a mask, whether it is a basic medical mask, a homemade fabric mask, or the more secure KN95 mask. In addition, most medical professionals are required at some point in their day to have and wear an N95 or KN95 mask

What’s the difference between an N95 and a KN95 mask?

KN95 masks are similar to N95 masks in the way that they are both made of the same or similar materials. In addition, they both protect against 95% of airborne particles that measure “0.3 microns or larger” (Dr. Michael Schivo). According to many online sources, after three days of use, both types of masks begin to lose filter function, and that number drops down to around “94.7%”.

The KN95 mask includes ear straps, while the N95 mask possesses straps that wrap around the back of the head. Essentially, these masks are very similar in the way they function and how long they can be worn. 

How long can you wear a KN95 mask? 

The KN95 mask, like the N95, is primarily for single use. However, due to occasional shortages, the CDC advised a rotation system: healthcare workers should have five masks, using one per day and letting each rest for at least five days between uses. This helps reduce potential contamination, as some pathogens might “die off” during the resting period. If reusing a KN95, store it properly and always check for wear or damage before reuse. Follow current health guidelines for the most accurate advice.

How Long Is the Mask Filter Good For?

As stated above, after about 2-3 days of wear time, the KN95 mask only blocks approximately 94.7% of airborne particles of that size. As you can imagine, the effectiveness of the mask’s filter decreases the more it is worn and suffers normal wear and tear. After the first couple of days, you will need to decide if it is worth it to wear a mask that is dwindling in effectiveness. 

Factors to Consider

Overall, it appears as though there are many factors to consider when thinking about changing your KN95 mask. If you are a medical professional, it is possible that your individual facility may have its own rules and requirements for wearing and changing out KN95 masks. If the decision is left up to you, please consider these four questions to help you make an informed decision on how long to wear your KN95 mask. 

1. Does Your Mask Still Fit Tightly?

Compared to other masks, the KN95 mask was manufactured to last. However, after extended wear time, the straps on the mask may loosen up, and your mask may become ill-fitting or even saggy. In addition to the mask’s filtration system becoming more and more ineffective the more days it is worn, loose straps will add to the number of particles that may make it through the barrier. Make it a point to pause and reflect on how well your mask is fitting. If it feels loose or if you can tell it is about to start sinking below your nose, replace it immediately. 

2. Is Your Mask Damaged or Dirty?

It’s safe to say that once your mask becomes damaged or even soiled, it is probably time for you to replace it. Damaged masks may include rips, loose ear straps, or even severely worn-out fabric. If you are a medical professional, it is always possible for your mask to become soiled with another person’s bodily fluids. To prevent yourself from contracting the CoronaVirus or any other kind of illness, consider replacing your mask if it becomes damaged or dirty. 

3. Did You Wear Your Mask Around a COVID-19 Patient or Close Contact?

Even if your mask does not appear damaged, loose-fitting, or dirty, it is possible for it to no longer be safe for you to wear. Medical professionals are often in close contact with COVID patients or possible COVID cases. If you have been in a room with a known COVID-19 patient, it is a good idea for you to go ahead and replace your KN95 mask. The CoronaVirus is known for living on fabrics and other materials for up to five days. Avoid touching the outside of your mask, and discard it if you have been in close contact or in the same room as a COVID-19 patient. 

4. Do You Have Another KN95 Mask Available? 

A damaged or loose-fitting mask is better than no mask at all. Right now, with quality masks so high in demand, it is possible that you will not have another mask available if you throw the one you have away. Of course, if your mask is severely damaged or soiled, you will need to seek out a different mask. However, we now live in a reality where you must first consider if there is another mask available before you toss away the KN95 you are currently wearing. 


Since there are no current clear-cut rules for how long you should wear a KN95 mask, you must decide for yourself what is best for your situation. Masks that are worn longer than two days are proven to be less effective in blocking particles and, although they were slightly less effective, they are still better than wearing no mask at all. Medical professionals who have been exposed to COVID patients should discard their masks regardless if possible. Here at CanGardCare, we will continue to keep you updated on all information regarding KN95 masks at the CoronaVirus. 

Article updated 2022-01-23.

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