N95 masks: 7 Things You Need to Know

Can you reuse an N95 mask? Are N95 masks effective against COVID-19?  This post discusses 7 things you need to know about N95 masks.

What are N95 masks?

N95 masks

An N95 mask is a type of respirator that can filter both small and large particles and liquid droplets when the wearer breathes in. It offers more protection against contaminated particles than a face mask does.

Compared to surgical masks, N95 respirators have a very a close facial fit. This explains why they have a very high fluid resistance. Some N95 masks are designed to have valves so that the wearer can easily breathe through. With these valves, unfiltered air is released when the wearer exhales. It is for this reason that questions have been raised by its ability to prevent the spread of COVID-19.

What does N95 stand for?

‘N’ is one of the National Institute for Occupational Health and Safety (NIOSH) certifications that apply to negative pressure air -purifying respirators. Other certifications are ‘R’ and ‘P’. These certifications do not apply to powered air purifying respirators.

N stands for ‘Not resistant to oil’. This means that they can be used in the work environment if no oil-based particles are present. They offer protection against solid and liquid airborne particles, but not against those that contain oil.

95 represents air filtration efficiency. This means that this type of respirator is able to trap 95 out of 100 particles.

What makes N95 respirators different from surgical masks?

Both N95 respirators and surgical masks are protective face covering whose use has become common all thanks to the outbreak of COVID-19.


Unlike N95 respirators which have a high filtration efficiency, surgical masks do not guarantee reliable protection against contaminated airborne particles.

Another difference lies in the certification and clearance for use. While surgical masks are cleared for medical use by the Food and Drug Administration, N95 respirators are tested and certified for use by the National Institute for Occupation Safety and Health.

The other difference is that while surgical masks are loose fitting, N95 respirators are designed to be tight fitting.

Are N95 masks effective against COVID-19?

The truth is, when worn properly, N95 masks are suffocating, uncomfortable and difficult to tolerate over long periods of time. If worn for a long time, tightly fitting N95 respirators may cause facial bruising.


Even though these types of respirators have a 95% filtration efficiency, their effectiveness can be compromised by small amounts of facial hair in the seal area.

Whether N95 masks are effective against SARS-CoV-2 virus (the virus that causes COVID-19) depends on whether they have a valve or not. According to guidelines released by the CDC, N95 respirators with valves are not meant for medical use.

In the event that the wearer is COVID-19 positive, vented N95 respirators cannot provide protection for those in close distance. These respirators, however, protect the wearer against the SARS-CoV-2 virus.

In situations where only vented N95 respirators are available, the exhalation valve should be covered a with cloth face. The cloth face should not interfere with the respirator fit.

Are N95 respirators for use by the general public?

No. They are not. This is according to guidelines provided by the Center for Disease Control (CDC). The CDC directs that N95 respirators are special personal protective equipment that should be preserved for frontline healthcare workers and medical responders.

The CDC recommends simple cloth face coverings for use by the general public when in a public setting. This will help slow the spread of coronavirus.

Are N95 respirators reusable?

Under normal circumstances, N95 respirators are intended to be used only once. But these are no normal circumstances.  There is a limited supply of these respirators thanks to COVID-19.

N95 respirators can be used more than once provided they are thoroughly disinfected. When properly decontaminated by methods such as by use of UV lighting, N95 can be used two to three times.

How to clean N95 masks?

There are various methods that can be used to clean N95 masks. The Key is that the cleaning method does not leave residual harmful chemicals on the material of the respirator. The respirator also needs to come out of the treatment as good as new. The method to be used also needs to be effective against the target organism, in this case, the SARS-CoV-2 virus.

Cleaning methods that reduce the filtration efficiency of the respirator should be avoided. These methods include washing the respirator with soap water or spraying with aerosol or liquid alcohol. These methods are not recommended for N95 respirators because they interfere with how the n95 filters small particles by breaking down its inherent electrostatic charge.

The three recommended methods for cleaning N95 masks are: by use of UV light, by use of moist heat, and by use of dry heat.

The use of dry heat is an effective method that can be used at home.  The dry heat method meets all the requirements demanded of a decontamination method. Dry heat is highly recommended because it is easily available. It can be generated by electric heating appliances such as rice cookers and ovens.

Use of Ultra Violet lighting is a low-tech and low-volume sanitization method suitable for healthcare workers based in rural areas. It is not a completely new practice as it has been used for cleaning hospitals in the US. The presence of substances such as cosmetics on the material to be cleaned may block UV light from working on that particular portion of the N95 mask.

When moist heat is used to disinfect N95 respirators for reuse, the SARS-CoV-2 virus and bacteria are also eliminated. The moist heat does not also affect its facial fit and functioning.


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