December 7, 2020 By admin Off

KN95 vs. N95 Masks | It Is Time to Use Common Sense

Summary of KN95 vs. N95 Masks:

KN95 vs. N95 Masks. Due to the shortage of N95 masks, we have to consider using equally effective alternate options. N95 is a certification issued by US authorities. Masks that have equally effective properties as N95 masks go by different names in different countries based on their independent certification systems. (KN95 – China, P2 – AS/NZ, 1st Class – Korea, DS FFRs – Japan). Considering the life and death situation we face in the hospitals, we have to push our health care administrators to consider getting us these equally effective alternative options since N95s are not available. At the end of the day, we have to prioritize our patient’s health, our health and our families health.

Learn about COVID-19 transmission on a separate blog post: How is COVID-19 Transmitted? What is the Right Mask for COVID-19? A Physician-Scientist’s Perspective.

Learn about COVID-19 test sensitivity on a separate blog post: COVID-19 Test Sensitivity is Unclear. How Accurate is COVID-19 Test?

We are in dire circumstances, and dire situations call for ‘out of ordinary’ actions.

I am an internal medicine physician, and I am exposed to patients under investigation (PUI) for COVID 19. Lack of appropriate PPE is putting me at high risk for contracting the virus. This is in turn putting my family and other sick patients I see at risk.

Cutting to the chase, we know that the N95 masks are an appropriate PPE for healthcare providers. Currently, the N95 supply is unable to meet the demand. Appropriately priced N95 masks are not available for bulk order at least until late April or May 2020.

Now, if you do not have access to N95, can you use equally effective alternative options (KN95) in the US hospitals/private practices/providers? Isn’t using these alternative options better than using a “bandana” or a regular surgical mask or a handmade cloth mask?

There are more than a few N95 equivalent masks available worldwide. As per a comparison study performed by 3M – it is reasonable to consider China KN95, AS/NZ P2, Korea 1st Class, and Japan DS FFRs as “equivalent” to US NIOSH N95 and European FFP2 respirators, for filtering non-oil-based particles such as those resulting from wildfires, PM 2.5 air pollution, volcanic eruptions, or bioaerosols (e.g. viruses).

These masks have similar superior properties as N95, but they go by different names based on where they are certified.
The WHO (World Health Organizations) considers N95 equivalent to KN95 and other similar masks. (WHO Article 1. WHO Article 2.)

Although the US authorities recommend using N95 masks, we have to take into account the current situation, and act accordingly. We need to prioritize the safety of our patients, families, and ourselves.

Do we let the current-day US regulations become a factor that determine if you – your family – your patients live or die?
I know it sounds dramatic, but that is the current unfortunate situation.

We should all reach out to our respective hospital/private practice leadership, to promote and advocate the use of equally effective alternate options for N95 masks.

If you own an independent practice, or if you have authority to pick your own PPE, you should strongly consider these equally effective alternate options (KN95 vs. N95) as opposed to other less effective options (bandana/surgical mask/cloth mask). After all, the end result matters in these circumstances, not how you achieve it.


Fit testing for respirator masks:

  • Fit testing performed by institutions ensures that the wearers have minimal air leak. Currently in the US, we do not have fit tested N95 equivalent masks readily available. The N95 equivalent masks are made by different brands, in different shapes, with a non-reliable availability and supply chain.
  • It is impossible to fit test every healthcare worker with every mask type. In this current dire situation that we are experiencing, one should think about the next best alternative to the fit tested N95 equivalent, which is a non-fit tested FFP2 or KN95 or other N95 equivalent masks. Healthcare workers should be able to trial the available models and use the FFP2 or KN95 or other N95 equivalent mask that fits them the best.
  • A randomized clinical trial (RCT) of 1,441 health care workers in 15 Beijing hospitals was performed during the 2008/2009 winter. Non-fit-tested N95 respirators were significantly more protective than medical masks against clinical respiratory illness. Rates of infection in the medical mask group were double that in the N95 group.
  • Unlike N95 masks, the KN95 and FFP2 masks are manufactured by hundreds of companies. They vary in shape, size and fit. It is important to use the one that fits you the best. There is no easy way to try out these options. In my case, I ordered small quantities of several models of FFP2 masks from China, fit tested myself, and picked the one that fit me the best.


Mask procurement difficulties:

This topic was excellently summarized in this NEJM correspondence: The New England Journal of Medicine – In Pursuit of PPE

FFP2 or KN95 are a good alternative, however we have the following challenges:

  • Concern for fake products with poor quality
  • Transportation delays, with new stringent quality control regulations from Chinese govt. (probably for the good)
  • MOQs are too high for regular clinics to afford.
  • US regulatory bodies trying to divert the supplies
  • Concern for improper mask fitting on the face. We usually cannot test the sizes of these masks before we order.


Custom fit KN95 masks:

After jumping through multiple hoops, we finally get hold of FFP2 / KN95 masks. That’s great, now we have masks with a good quality material that can defend us against the virus. Problem is, they are one size fits all – regular size. This results in a poor seal, and a high risk for air leaks. We have to use some street-smart tricks to make sure that the mask creates a good seal.

We have been using two techniques to help customize the masks to the wearer, and secure a tight seal:

  • Adjusting the size of elastic straps by tying a knot at the end of the straps. This reduces the length of the straps to the desired fit, thereby creating a tight seal to prevent any leaks.
  • Nose bridge is another common site for an air leak. We bought aluminum nose clips that are bendable and have a self-adhesive on one side. We stick these strips on the nose bridge part of the mask, to make it a compact and tight fit on the nose. This prevents fogging of glasses, and also prevents air leaks.

The eventual goal is to prevent any air leaks. Unfortunately, the design/material of surgical masks and bandanas (home made masks) create too much air leak. There are many common misperceptions of what masks to use, and when to use. Please refer to this detailed post that summarizes the use of masks in COVID-19 –


If you need N95 masks, fill out the details here. I will forward that to a few bulk manufacturers.

I hope we have access to the appropriate PPE that we need to take care of our patients and our families.

Learn about the right mask to use for COVID-19 on a separate blog post: What is the Right Mask for COVID-19? How is COVID-19 Transmitted? A Physician-Scientist’s Perspective.

Learn about the accuracy of COVID-19 test on a separate blog post: How Accurate is COVID-19 Test? COVID-19 Test Sensitivity is Unclear.

Keywords: KN95 vs. N95


KN95 vs. N95