December 8, 2020 By Off

N95, KN95, R95 and P95 (Differences and Reuse)

A face mask or respirator is invaluable in 2020 following the outbreak of the new coronavirus. However, its functionality predates the novel pandemic. Masks come in various types and capabilities, but manufacturers generally design them to filter air pollutants, pollen and smog. You can also find masks that can filter bacteria and germs, automobile exhaust, animal allergens, odor, fragrances and more.

Some masks can filter all the allergens and pollutants, while others only protect you from a few. As such, it is essential to compare your offers and make a choice based on what you need. Face masks also influence the air quality you breathe, so you want to ensure that it’s safe and easy to use. Here is a brief comparison of N95, KN95, R95 and P95, which are said the most effective among other masks you can possibly get on the market.

Differences between N95, KN95, R95 and P95 Mask/Respirator

If you have extras, please consider donating some

The new COVID19 pandemic highlighted the mass shortage of medical personal protective equipment (PPE) for doctors, nurses and other healthcare workers.

They are our heros fighting on the frontline, saving lives and protecting our communities. You can keep a few for youself and your family. But, please consider donating some to those who need them, if you have extra respirators.

With slightly different designations, these four types of mask have similar features concerning what matters most to users. But, you can make full use of them by understanding their differences. After all, high-performance masks will remain valuable for awhile.

Also read: How Long Do N95 Masks Last (And Are They Reusable)

Applied standards

The National Institute for Occupational Safety and Health (NIOSH) regulates mask classifications and provides three letters for the same purpose. These are N, R and P.

  • N is used to denote respirators that are not oil resistant,
  • R for masks somewhat resistant to oil-based particulates (it’s NOT for ‘Reusable’!), and
  • P for masks that are oil-proof.

The number ’95’ (or ’99’ and ‘100’ you may have seen somewhere), are percentage ratings. Masks rated 95 can filter up to 95% of particulates of 0.3 microns or bigger in diameter, while 100 rated respirators filter up to 99.97% of the contaminants.

Likewise, KN95 is a grade specified by equivalent Chinese national standard (GB2626-2006). So, N95 and KN95 masks basically have nearly equal functionalities, as both can filter 95% of non-oil particulates. As the US goverment imports more medical supplies from around the world, chances are you could also find masks with the following designations:

  • FFP2 (EU EN 149-2001)
  • P2 (Australia/New Zealand AS/NZA 1716:2012)
  • KF94 (S.Korea KMOEL-2017-64)
  • DS2 (Japan JMHLW-Notification 214, 2018)

These are standards equivalent to US N95 and masks/respirators carrying above codes provide nearly the same protection. 


N rated masks are made using tough, flexible melt-blown nonwoven polypropylene fiber. R rated and P rated filters usually feature the polypropylene component with the addition of a fume protecting carbon layer that can prevent oil-based particulates from passing through the mask.

The respirators might also include plastic and rubber parts, so materials vary depending on the type of mask and its rating.

The work environment will also determine the type of filter or cartridge required for efficient filtration. The filtering face piece may feature cloth-like material, while the other parts, such as cartridges, are made using a variety of materials, including silicone, neoprene and rubber. Strap harness or ratchet suspensions may also feature different materials.

N95 vs KN95 vs R95 vs P95 meltblown fabricsImage:

Filtration efficiency

A respirator uses a filter or cartridge to prevent specific particulates from passing through to the user’s lungs. Filtration efficiency is measured based on the percentage of particulates the mask can filter.

There are three primary ratings for filtration efficiency. According to studies, a standard N95 face mask can filter 95% of non-oil particulates measuring 0.3 microns or bigger while an N100 mask will filter 99.97% of all the particulates. N99, on the other hand, has a filtration efficiency of 99%.

N95, R95 and P95 all have a filtration efficiency of 95%, albeit for different particulates. As a general rule of thumb, N rated masks are suitable for environments free of oil mists, while P rated mask can work in oil mist environments, but only for a single 8-hour shift.

Note: No filter provides 100% proofing against the contaminants and particulates.


Each respiratory protective device is for specific applications and work environments. Standard N95 masks can filter up to 95% of non-oil airborne particulates 0.3 microns or larger. These are general purpose respirators that can protect users from dust, dirt, allergens and other airborne pollutants. However, the N rating means these respirators are not capable of resisting oil-based particulates, such as lipid substrates and oily mist.

Note: R95 masks can filter oil-based particulates but aren’t entirely oil proof as P95. It is essential to restrict usage to the purpose recommended by the manufacturer.

Some masks are designed for dust and allergens, while others specifically protect users from specific bacteria. As such, you should review the respirator’s purpose before purchasing or using it for any reason.

Oil resistance

N95, KN95, R95 and P95 all filter 95% of the particulates they keep off. However, the different letters in their respective names specify the types of contaminants they can filter.

The mask classification is according to their ability to filter oil-based particulates. N95 and KN95 offer zero resistance to oil so you shouldn’t use them in environments that feature airborne contaminants with oil shells around them as this will allow the contaminant to pass through to the user. 

R95 is resistant to oil, but not all substrates. If you want a fully oil-resistant face mask, P95 is your closest solution. You can also purchase P100, which offer 99.97% filtration efficiency and is oil proof. P100 is also the top-rated respirator of all nine classifications provided.

Oil resistance is essential to review since some viruses contain a lipid shell that can penetrate masks without sufficient resistance.  

Are N95, KN95, R95 and P95 masks safe against covid-19

The current global pandemic is caused by covid-19, a kind of novel coronavirus, which is also called SARS-COV-2 by US researchers. Scientists have found the culprit and measured their size, ranging from from about 60 to 140 nm in diameter.

As we just mentioned above, respirators rated “95” are able to stop 95% of 0.3 micron (300 nm) particles from entering our breathing tract. Aparently, covid-19 virus is smaller than 300 nm. Does that mean N95, KN95, R95 and P95 masks are nothing more than decorations?

Sit back and relax a bit. The truth is that most coronavirus spreads by tiny, airborne droplets of fluid when a carrier coughs or sneezes. The size of droplets is generally larger than 500 nm, meaning that normally functional N95, KN95, R95 and P95 masks can protect you from most fluid droplets.

However, masks alone will not be adequate to keep coronavirus at bay.

N95 vs KN95 vs R95 vs P95 goggles

In addition to droplets, coronavirus also spreads through contact with contaminated surfaces. That’s why CDC and other health orgainzations recommended or highlighted other best practices, such as washing hands using alcohol-based sanitizers and social distancing.

It’s true that you can use all four masks to help slow down the spread of covid-19. However, for anyone working at a medical facility visited by infected patients, who may be asymptomatic, it is essential to find a premium quality face shield or goggles that will protect you from the virus trying to get into your body via your eyes.

How to Disinfect and Reuse Your N95, KN95, R95 and P95

Note: N95, KN95, R95 and P95 masks are disposable medical gears, meaning you use it once and discard it. We talk about reuse merely because there is a shortage of them and reuse or extended use is a stopgap strategy. 

Reusing masks is a strategy that can reduce your expenses and trips to the shop, which helps to ensure social distancing and conserve your medical resources. Whether you use homemade cloth masks that can be hand washed or have the advanced N95, it is essential to disinfect your mask if you plan to reuse it.

Surgical masks and protective respirators, such as N95, R95 and P95, are designed for single shifts, so you should dispose of them after the shift. However, some offers can be disinfected and reused. Here are some best practices for reusing and disinfecting respirators.

Keep them away from oily stuff

As we said before, N95 and KN95 masks are not resistant to oil. Oily residue can disable electret of the mask fabric, or attract other dirt and dust, promoting the growth of bacteria and other organisms that feed on the oily substances.

As such, you should clean or dispose of your mask if it has oil, grease, fat or lipid residue. Keeping the respirator away from oil and other dirt also reduce the rate at which your mask gets dirty.

Keep them in a dry, breathable container such as paper bag

Your N95, KN95, R95 and P95 masks should be stored safely whenever you are not using them and the best storage environment is a dry, breathable container.

This protects the mask from gathering moisture and getting dump, thus reducing the number of germs and bacteria. You can use a paper bag, which is the easiest way to keep your respirators dry and safe.

Pay a great attention to seal check (nose stripe, face contouring)

Always practice a seal check after putting on your masks. This ensures the air flows into your respiratory system through filtration fabrics instead of gaps between your face and mask.

It’s easy to understand, right? If the mask failed to contour your face and the air just find its way in via leaks around, why bother to wear one. You should check the nose strip, mask contouring and other parts to ensure good sealing.

FAQ about Mask Reuse

1. Can I wash them with water and bleach/soap?

No. While it seems like the most effective way to disinfect a face mask, you should never clean your N95, KN95, N99, N100 respirators or surgical masks using water and bleach soap.

To be more specific, any masks made of melt-blown PP nonwoven should be kept away from washing, steaming, boiling or using alcohol-based sprays, which will destroy the electret (electrostatically charged media). You can compare the effects of different decontamination methods here.

2. Can I disinfect them with alcohol or alcohol-based sanitizers

No. It isn’t advisable to spray your surgical masks using alcohol or alcohol-based sanitizers in an attempt to disinfect them. These masks feature a thin waterproof coating that prevents water and other liquid droplets from passing through. Using alcohol disinfectants will dissolve the waterproof layer leaving making you vulnerable to infection. Here’s more on why you should avoid using alcohol sanitizers on your face masks.

3. Can I disinfect them with UVC?

No. Using ultraviolet germicidal irradiation (UVC) can degrade the polymers used in standard N95, KN95, R95 and P95 respirators and a surgical mask.

Using them on disposable masks will quickly degrade the mask’s ability to protect the user for the recommended duration or number of reuse. Read more about why you should avoid UVC mask decontamination.

4. Can I use old but intactly packaged masks?

Yes, if they are not “too old”. According to this study about  using old N95 face mask, N95 respirators remains functional after years in storage under good conditions.

The sample fabrics from N95 respirators stored for six years showed satisfactory filtration performance. So, it’s reasonable for us to presume that KN95, R95 and P95 respirators also have similar if not same durability.

5. Can I put used masks under sunlight?

Yes, for a limited duration. You can leave your mask under sunlight, especially when you want to disinfect it by drying up moisture. Dryness also inactivates the virus, so you can air it to reduce the chances of infection and kill any germs that cannot withstand direct sunlight.

However, too much sunlight exposure can degrade the material by accelerating its aging. 

6. Can I make masks with HEPA vacuum bag?

It is not recommendable. Some HEPA vacuum bags feature microscopic fibreglass that can be harmful to the human lungs when inhaled.

Therefore, manufacturers warn users about repurposing their filters for coronavirus and prohibit using them to cover the nose and mouth for any purpose. Here’s more information about why you shouldn’t use HEPA vacuum bags to make face masks.

If you want to make some filtration inserts out of HEPA material for your cloth face coverings, it’s important to make sure that your HEPA vacuum bag is fibreglass free. 

7. How many hours can I wear N95, KN95, N99, N100 respirator?

You can use respirators, such as N95, for up to 8 hours before discarding them. However, you should replace your respirator once it is wet on the inside, dirty, torn or deformed.

Also, extended use of these respirators can cause difficulty breathing, mask acne or some other skin issues. So, personal skincare is another job you might want to deal with. 

Spread the word, protect yourself and help fight against the pandemic

N95 vs KN95 vs R95 vs P95 measures

To Wrap Up

There are nine different classifications of respirators available in the market. Each category has specific features and capabilities, so it is crucial to choose the right mask for your requirements.

If your operation requires resistance against oil, lipids and similar substrates, P95 is more suitable. On the other hand, if all you need is a simple respirator for general aerosols and contaminants, N95 or KN95 will suffice.

You might also want to compare filtration percentages depending on your operating environment. For instance, if you need augmented filtrations, N100, which filters 99.97% of non-oil pollutants, offer a better choice than N95, KN95, FFP2 or KF94.