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What Are Particulate Masks?

To non-medical workers, it may seem as if face masks are relatively new to the scene. Outside of hospitals and dentist offices, you may not have seen them much until recently. However, there are many types of masks that were already in use without medical context, to protect against pollutants like dust, ash, or smoke.

These particulate masks are now highly sought after as protection against COVID-19. But are they effective and if so, who should actually be using them? In this article, we’ll learn more about particulate masks, including what they are, how they work, and how useful they are against the coronavirus.

What is a particulate mask?

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Particulate, or particle, masks are specialized masks used to purify inhaled air. Such masks filter the air that passes through them, leaving it free of harmful pollutants. 

These respirators are only effective when used against solid particles. They are powerless in the face of gases or vapors. Some of them may even be useless in shielding against oil, which we’ll discuss in a moment.

They are, however, approved by the National Institute for Occupational Safety and Health (NIOSH). They must pass NIOSH safety standards before being stocked and sold by third-party companies.

Below is a list of the types of NIOSH-approved particulate respirators available in the market:


The N95 is perhaps the most commonly-used respirator out there. It is typically employed by construction site workers or scientists and field researchers who are in frequent contact with volcanic ash and similar pollutants in the surrounding air. 

N95 respirators belong to the N-series masks, in which the N stands for “Not resistant to oil-based particles.” This means that N95 respirators cannot provide complete protection against oil-based pollutants. N95 respirators can filter out 95% of particles that are larger than 0.3 microns.

Surgical N95

This is a specialized type of N95 mask that is approved by the FDA and meets NIOSH standards. It can be used during surgery by medical staff, and will effectively serve as a barrier against pathogens.


This mask is similar to the N95, but blocks a higher percentage of particles. It is not resistant to oil-based particles and can filter out 99% of particles that are larger than 0.3 microns.


This type of respirator is less common than other N-series respirators. It is also harder to breathe through, thanks to its intense filter density. This mask can filter out approximately 99.7% of pollutants present in the air as long as they are larger than 0.3 microns. 

It is not resistant to oil-based particles, but is extremely useful in combating other harsh pollutants, like volcanic ash and cement dust, that can damage the respiratory system.


R95 masks are not as well-known as the N95 mask but have many excellent uses. Some may argue that this mask is more useful than the N95 because it is “somewhat” resistant to oil-based particles. (The “R” stands for “Resistant to oil-based particles”.) 

Similar to the N95 mask, this respirator can keep out 95% of particles that are larger than 0.3 microns in diameter.


This is one of the most effective and useful masks out there. The P95 can keep out up to 95% of pollutants found in the air, including those that are lipophilic, or oil-based particles. According to the CDC, this mask is “strongly resistant to oil”. 


This is similar to the P95, except that it can keep out up to 99% of airborne particles, including oil-based ones.


P100 filters can stop 99.7% of toxic particles in the air from entering the wearer’s respiratory system. This mask is highly resistant to lipophilic, or oil-based, particles.

How to tell if your particulate respirator is genuine

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A genuine particulate respirator will be NIOSH-approved. Here’s how to tell if that’s the case:

  • The mask will bear the name of a well-known and well-reputed company, like 3M or Honeywell Safety. These companies will be registered and recognized by NIOSH.
  • It will also have “NIOSH” printed on it in block letters, or bear the NIOSH logo.
  • The mask will be listed with a number either on the filter itself or just on the packaging. This is called the NIOSH testing and certification approval number, e.g., TC-84A-XXXX.
  • The mask will fall under one of the following categories: N95, N99, N100, R95, P95, P99, P100.
  • The mask will have a model number or part number. This is the approval holder’s respirator model number and is represented by a series of numbers sometimes accompanied by letters, e.g., 8577 or 8577A.

How to wear a particle mask

To be of any use, particle masks like the N95 respirator must be worn correctly. These masks are designed to cover the mouth and nose region, and their edges should always be in direct contact with your facial skin. For this reason, people with a beard may not be able to wear this mask properly. 

Begin by placing it over your mouth and nose – the mask should cover both, and the edges should maintain contact with your skin. Next, use the elastic bands or cloth ties at each corner to secure the mask in place. You may tie these bands behind your ears or tie them around the back of your head.

Finally, make sure that the mask is secured by rechecking the ties and ensuring that your filter, or the respirator’s cup, is touching your face at all times. Check that there are no gaps between the mask and your face as these could allow particles from the air to enter.

Can you reuse particulate masks?

Many people have taken to reusing their particulate masks due to a severe shortage of supplies. The coronavirus pandemic has placed a serious strain on the healthcare sector, including official departments in charge of manufacturing NIOSH face masks.

As a result, doctors, nurses, essential workers, and others who are in contact with the coronavirus have begun to reuse their particle masks. Though the CDC states that it is possible to reuse these masks safely to some extent, it is inadvisable for a number of reasons and they should be disposed of after a maximum of eight hours of use, if possible.

This is because these masks trap a large number of pollutants and harmful particles over time. These particles then stay trapped inside the filter. Reusing this mask means that the wearer is exposed to these harmful trapped particles for longer.

Another reason why these masks should not be reused is that they become more difficult to breathe through over time. This, too, is because the mask’s filter fills up with pollutants, and the microscopic air spaces within the filter fill up to a point where very little air can pass through it.

Who should be wearing these masks?

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Particulate masks should be reserved for medical workers if at all possible for the duration of this crisis. This not only keeps healthcare staff at a lower risk, but prevents asymptomatic carriers from passing on the virus to uninfected patients. Other people who wish to follow the CDC’s recommendations and wear a protective face-covering in public should consider a cloth face mask, instead.

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