Particulate Filter Efficiency (PFE) is the standard by which masks are evaluated.

We test to both the ASTM standard and the NIOSH using a PFE machine.

The machine then uses optical scanning technology to report how many particles slip through.

Passing the Filtration Test

For N95, KN95, and KF94 respirators we are applying the NIOSH standard and testing with .3 micron particles of NaCl.

For Surgical and Non-medical 3ply masks we are using the ASTM Standard with .1 micron latex particles.

For Respirators to pass:

  • N95 Respirators = 95% or higher
  • KN95 Respirators = 95% or higher
  • KF94 Respirators = 94% or higher

For Surgical Mask to pass:

  • ASTM-3 = 98% or higher
  • ASTM-2 = 95% or higher
  • ASTM-1 = 95% or higher
  • Non-medical 3ply masks = 95% or higher

Breathability Testing

Air flow resistance is tested in Pascals (pa) to determine how breathable the mask is. Our machine is calibrated to test from 0 - 600pa. Since we are testing for resistance, the lower the resistance, the more breathable the mask will be.

Experts say that a resistance of less than 15 ML/H2O (or 150pa) is ideal for a mask that you wear all day long, but we have found that masks in the 100pa range are much more comfortable.

Surgical masks, N95 masks, KF94 masks, and KN95 Respirators all have different standards for what is considered good breathability, which is reflected in our scoring.

Passing the Breathability Test

  • N95 Respirators = Below 250pa
  • KN95 Respirators = Below 250pa.
  • KF94 Masks = Below 250pa
  • Surgical Masks = Below 150pa

Standards Evaluation

Does the mask adhere to the basic rules laid out by the standard they are claiming? A good example of this is in the text written on the front of N95 and KN95 masks. The standards for each of these masks demand that very specific information be printed on the device. If a KN95 mask does not have the manufacturer name and the standard number they are meeting (GB 2626-2019 or GB2626-2006), then they cannot be considered KN95 masks. Another example is that to meet the KF94 standard the mask must be constructed in South Korea.

When masks fail to meet these very basic requirements they are given a failing grade even if filtration and breathability scores are good. Our belief is that if they are skipping these basic parameters, what other corners have been cut?

Subjective Scoring: Construction

Ear loop strength, build quality, and comfort. This test is somewhat subjective, which is why we don’t include in pass/fail analysis. However most masks that fail our testing also have issues with the following:

  • Design flaws: Is the mask constructed correctly? Are the earloops welded to the correct side of the mask? Etc
  • Nosewire quality: If the nosewire is ineffective or poorly assembled?
  • Earloop Strength
  • Airgap seal: If the earloops are too loose the mask doesn’t seal correctly.

Subjective Scoring: Smell

What (if any) odor is the mask giving off. This is the most subjective of the tests, but also incredibly important. Smell is not considered as part of pass/fail analysis.


This data should be used for educational purposes only. It's not official. We are not a government agency or certification house, we are a mask manufacturer so your mileage WILL DEFINITELY VARY.

We are only testing one mask in a box of 5 to 100, and that's just one box in millions that a manufacturer makes. There's really no telling what happened to a mask before it got to us, and many times we find while one mask in a batch tests poorly, the other masks are just fine. That said, it's our opinion that the best manufacturers do not let bad masks out of their factory.

Speaking of opinion, that's all you are going to get here. Opinions, not official results. Please consult the manufacture or relevant government bodies if you're looking for official data--we are only posting here because, well, the authorities haven't done anything like this.

Legal stuff:

Armbrust Inc. makes no representation as to the authenticity of the samples received and assessed. As part of its standard respirator approval process for NIOSH-approved respirators in the United States, NIOSH conducts a comprehensive quality assurance review of the quality process and manufacturing site. None of these reviews were conducted during a NIOSH assessment. Further, no certificates of approval were provided with the samples. Therefore, validation of the claims that the product meets a particular international standard cannot be made.

The results of these tests are for the sample tested and may or may not be representative of a larger lot or population of similar respirators. The results of any filter penetration test can only be used to provide a check of the product’s filter efficiency. No conclusions can be made regarding equivalency to N95 products that are NIOSH approved.

No certificates of approval were provided with the samples received. Therefore, the authenticity of the claims, that the product meets a particular international standard, cannot be validated.

Most of these products have an ear loop design. NIOSH-approved N95s typically have head bands. Furthermore, limited assessment of ear loop designs, indicate difficulty achieving a proper fit. While filter efficiency shows how well the filter media performs, users must ensure a proper fit is achieved.

These results are not to be used by manufacturers, distributors, suppliers, and importers to make claims about their products and/or to influence purchasers.

1 comment

I am confused and don’t know what to purchase. I have been told that the N95 is made in the USA, but they do not come in color or fit behind the ear.

Mary Means January 19, 2022

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