Barrier Face Coverings

Different occasions call for different types of masks and respirators. Where you happen to be, for instance in a grocery store or crowded park, will change what mask you ought to wear. There are other factors that should influence your decision as well, such as the weather and the proximity of other people. It is always best to err on the side of caution. PPEHOTLINE recommends choosing high-efficiency masks for:

  • All indoor settings where individuals are present.
  • Poorly ventilated rooms where individuals were present before you.
  • Outdoor areas where social distancing is not possible.

High-Efficiency Masks and Respirators

A high-efficiency mask is one that addresses at least six components of a safe mask: Filtration Efficiency, Fit, Seal, Breathability, Durability, and Reusability (FFSBDR). While we prioritize these characteristics in this order, there is room for other valid considerations. Selecting transparent masks would be considerate for deaf and hard-of-hearing individuals. Using masks that allow for good voice clarity is also important, especially if you carry out a job that requires you to talk to a lot of people whilst wearing a mask. Nonetheless, we believe such factors should not take primacy over filtration efficiency. We also believe that people are better protected by wearing one high-efficiency mask than many double masking practices. Likewise, wearing a mask with more layers does not necessarily mean better protection.

There are many organizations seizing the opportunity to innovate a modern mask, one that addresses the characteristics above. We recommend doing thorough research when deciding to invest in your health and safety through any product, making sure the necessary standards are being met.


Mask Filtration efficiency

Filtration efficiency (FE)

Filtration efficiency is a measure of the mask’s ability to protect the user from droplets and aerosols  that can penetrate through the filter material. The higher the filtration efficiency for smaller aerosols, the safer you are. We recommend looking for a filtration efficiency for particles of size 0.3 microns, as this is the most penetrating particle size through filter media for breathing. For example, a mask with 95% FE for a particle size of 0.3 microns would allow a maximum of 5% of airborne particles to penetrate through the material, (or reduces particle concentration by a factor of 20).

Mask Fit


Fit mostly refers to the size of mask you want to use. While you preferably would measure your face, in doubt, we recommend to lean towards a smaller size. A mask that fits well allows the air to flow maximally through the filter as we inhale and exhale and not through gaps between the mask’s edge and the face. For instance, masks and Half-facepiece respirators with soft (silicon) cushions can close these gaps efficiently. Too often, the gap around the nose bridge causes a greater challenge that requires a better sealing.

To ensure a better seal, we recommend using masks or respirators with full-head loops instead of ear loops, as this helps ensure a better seal. Note that facial hair can be a significant obstacle in achieving perfect fit, which is less likely to be achieved without the use of positive air flow provided by a Power Air Purifying Respirator (PAPR). Try to keep using a consistent brand and size, once you find the product that fits you well, but be sure to continuously check the seal.


To check how well a mask is sealed to the face, we should be testing by mimicking the different scenarios we might find ourselves in: moving our head and jaw in different directions, widening our mouths, speaking, and bowing to name a few. You may notice where the air from your inhale is coming from. Remember, air flows in the direction of least resistance: when inhaling, if it is easier for the air to come through the sides of your mask, it will do so. For example, double masking of some single-use High-Efficiency masks may gradually lead the air to follow between the mask’s edges if the sealing is not tight enough for air to mostly pass through the filtration material.

Instead of double masking to improve the sealing, we recommend using good quality mask braces and nose wires. For instance, heavy duty aluminium nose wires could mold better to the shape or your nose without getting loose over time. Nevertheless one should repeatedly check the seal of the mask.

You can (1) refrigerate Eyeglasses (or any glass material), (2) defog it once you take it out of the fridge, (3) hold it around your mask, next to your the borders of the mask and your skin (near your cheekbones for example), (4) and while you exhale, the glass will fog again if there is a gap.


Breathability is a measure of how difficult it is to inhale and exhale through the mask. This is commonly expressed as a pressure drop, which indicates inhalation resistance across the fabric layer: the lower the pressure drop value, the easier it would be for someone to breathe with the mask on.


Durability refers to the life cycle (mechanical ‘fatigue’) of the mask. Most masks have a point of diminishing-returns (using it after many hours might cause a severe drop in filtration efficiency, increased leakage, or collapse of the mask). Durability also refers to whether a mask can be reused or cleaned. Essentially, durability is all about how many hours you can wear the PPE without it collapsing and becoming damaged and/or ineffective.

Mask Resubality


Masks and respirators that are made of a food grade synthetic such as silicon, or natural rubber material, can be used, cleaned, disinfected, stored, and re-used. Reusable masks are much favorable from an economic perspective but also the user’s safety. They also have the added benefit of contributing less ecological stress in regards to waste. It is important to properly clean those masks. Note that single-use masks tend to lose their filtration efficiency after each use.

High-Efficiency masks with an exhalation valve

A High-Efficiency mask with an exhalation valve provides an outstanding respiratory protection to the wearer and can also reduce particle emissions to levels similar to or better than those provided by surgical masks, procedure masks, or cloth face coverings. However, the use of an electrocardiogram pad or surgical tape secured over the valve from the inside can further reduce particle emissions. (Source: DHHS (NIOSH) Publication Number 2021-107)

Mask Production Process and Material

We recommend checking the mask against any noxious production process and materials. For example, the use of heavy metal-based antimicrobials or other toxic inhalable substances, as well as some synthetic fabrics might be harmful.

Counterfeit Masks are Flooding the Market

There are corporations that might not always audit the authenticity of their manufactured masks; therefore, end-users who purchased from random stores/distributors are left uncertain whether they’re open to more risk than they’re aware of. We recommend individuals to purchase from suppliers who they can trust, most often by a nation-state’s occupational safety and health authorities; nonetheless, be fully aware that stamps and markers from such bodies can be easily fabricated. One should also not rely on product reviews of other users, as those can be fake. Relying on the labels, marks, logos, description, or stamps on the product or it’s box is not enough, as those are the easiest to fake. One needs to cut the layers and check the mask itself.

Not Fake, but

  • Some masks might not be fake per se, but don’t provide the needed protection. For example, most KN95 masks imported from China don’t meet filtration standards. However, the KF94s, which are essentially the South Korean equivalent of the N95s/FFP2s might be a better option in blocking SARS-CoV-2 particles.
  • We also advise that you take precaution when reviewing data regarding the filtering efficiencies of masks, seeing as some claim over 90% filtration efficiency, but do not disclose if it’s against droplets or aerosols. For example, a mask with 99.99% protection against droplets, but low efficiency against aerosols doesn’t provide you a safe protection against the coronavirus. However, a mask with high filtration protection against aerosols also protects you against droplets.
  • The overwhelming majority of cloth-based masks pale in comparison to the high-efficiency PPE, in terms of user-safety. Compared to other personal safety equipment, including helmets, seatbelts, parachutes, and infant car-seats, most Covid-19 related consumer masks are not subject to assessments and stringent standards. Products being sold without transparent data or usage guidance leave people uninformed and potentially exposed to greater risk. PPEHOTLINE shares some general educational material to empower end users.

Designer printed masks

The request for printed masks with fashionable graphics is increasing. Whilst we understand that the look is important for some people, we recommend checking the corresponding safety certificates and making sure that your masks are printed with non-toxic, azo-free dyes. The pigments and printing materials should not contain hazardous particles, which can be detrimental to your health; for example, formaldehyde commonly found in commercial products, is a potential cancer causing chemical that should also not exceed the legal limit. All in all, it is always best to ensure that the product has been tested thoroughly before you decide on purchasing it.

The proper usage of the mask is as important as having the right mask. Please learn about the proper usage.

Blocking and filtering of the viruses is not enough, we also need to destroy them. Here you can learn more about decontamination.