Masks and their efficiency, all you need to know!

8 min

Owing to the pandemic of COVID, we are well aware of the concept of masks and their usage. However, there are mixed feelings and opinions on this. Some regard them as indispensable, while others constantly argue over the use of masks. But, it has become an inevitable part of our everyday lives or rather, the new normal. Most of us have a lot of confusion revolving around masks. It ranges from the types available, their efficiency, usage, etc. In this article, let’s decode the mystery behind, and get an idea of which are the most suitable ones to use.

In simple words, masks are a piece of cloth or any material that acts as a shield. It covers the regions around the nose and mouth. It acts in 2 ways- protects us from exposure to unwanted contaminants like dust, pollution, droplets, etc. They also protect people around us, by reducing the risk of contamination or exposure from us.

Why wearing a mask is so important?

In today’s scenario, all of us are well aware of the rate of spread of COVID. Masking is a very important part of everyday life. It is absolutely important to curb the spread of COVID and reduce the rate of spread. Because prevention is the first step for good health. It not only keeps us safe but everyone around us too.

COVID 19 is a respiratory virus and the spread is kind of similar to that of the common cold. It spreads through suspended air droplets and contact with an infected person (Sneezing, coughing, talking, etc.)

Data has shown that states which had higher compliance wearing masks showed a lower number of cases. In addition, people wearing masks were protected well even when exposed to patients with active COVID infection under a lot of circumstances.

And still, there are a lot of studies on this virus. Until we find a perfect solution to the problem it is always better to stay safe and protected.

Various types of mask and their efficiency:

N95 masks:

To begin with, the ‘N’ of N95 stands for non-oil meaning absence of oil based particulates in the mask.

The ‘N’ is a rating letter. It indicates that the mask is suitable for wear in a workplace environment.

The number 95 indicates the mask’s efficiency. So, these masks have 95% efficiency.

KN95 :

Almost similar to N95s. Can be used as an alternative to N95.


Surgical masks are not as effective as the N95s and KN95s. But, they are still a good option to use.


Cloth masks are the most regular and convenient masks used today. The biggest advantage is that they can be washed and re-used. The downside is that these masks have larger pores than surgical or N95 masks. But cotton also absorbs a high percentage of droplets and particles. They are also soft, cool, and breathable.

Hence, layered masks offer better protection.


Sometimes people use fancy scarves as shields. They are mostly ineffective.

Some of the other alternatives include,

KN 95 with fitted respirators:

This too filters 95% of the particles with an additional respirator to help in breathing.

Filtering face masks:

They mainly filter out the dust, dander and pollen.

A P100 respirator:

Not used commonly by the public. This mask is for people with occupational hazards like asbestos, chemical, etc.

A full face respirator:

This is an alternative option for people with breathing trouble using surgical masks.


So now, let’s rate some of the common types of masks we know from best to worst (based on the studies done by Duke University). The study tried to figure out how to quantify how good the mask works. In this study from Duke’s university, they used a LASER, camera, and an algorithm to calculate the number of droplets from the wearer. Data was compared to a test subject who wore no mask.

N95 :

Without much surprise, this is one of the most effective ones available in the market for use. This is especially worn by health care providers and front-line workers (due to their high efficiency and constant need for protection due to close contact with patients all the time). Oftentimes a fit test is performed to ensure a better seal. N95s can be really uncomfortable when worn for long hours due to the fit.

N 95s were initially used by doctors when they were dealing with patients having TB, SARS, or other aerosolized infections.

During this active COVID pandemic, procedures like intubation and dental procedures like scaling or preparations of the tooth using devices like aerotors require these masks. This is essential to prevent smaller droplets from entering.

It gives the strongest protection. The filtration rates are

  • 95% for viruses
  • 100% for bacteria, dust, and pollen

KN 95 :

It is almost like the N95 masks. Following N95, KN 95 is the second-best mask available in the market.

They filter out 95% of particles that are 0.3 microns in size or larger. They achieve this filtration through multi-layered polypropylene melt-blown non-woven construction.

Like N95 they are light-weight, disposable and have elastic ear loops.

To check the quality or genuineness of the KN95 masks a flame test can be done. In this test, the mask melts but does not ignite.

However, N95s with valves were not a very good option. These valves allowed the escape of smaller droplet particles from the wearer. It also does not provide an ultimate protection from the environment.


Made of non-woven fabric. They are disposable or single-use. Mostly preferred for medical and dental use. They are used by doctors to prevent patients from getting infected by them. For example through droplet infections like influenza. After N95 and KN95, surgical masks are the 3rd best ones to use. The number of layers varies in these. It is important to note that disposable masks and surgical masks are not the same.

A mask that is equally effective to these is the washable polycotton ones. Their efficiency rates are,

  • 95% of virus
  • 80% for pollen, bacteria, and dust.


The FFP stands for Filtering Face Pieces. They are the type of masks that fit snugly around the chin and filter the particles. There are three classes according to the filter penetration limit.

According to the filtration of airborne particles, FFP1 can filter 80% (at 95L/ min air flow)- Yellow elastic band

FFP2 (blue or white) and FFP3 (Red) can filter up to 94% and 99% respectively.

They have the ability to isolate suspended particles.


Carbon filter masks are effective for filtering out air pollutants. But, it does not effectively filter out viruses and bacteria. They mostly bar out odour and their efficiency rates are,

  • 10% virus
  • 50% of bacteria, dust, and pollens.


They are regular DIY masks and do not serve much use. According to a survey, they only block a third of the particles compared to the surgical ones.

Their efficiency rates include,


Mainly serve fashion purpose.

The efficiency rates include,

  • No filtration of viruses
  • Very minimal filtration of bacteria, dust, and pollens (5%)

So, something even more worse than cloth and sponge masks are,

Bandanas and gaiters:

The reason these are regarded as the worst types of shields is, they break down big droplets into multiple small droplets and disperse them.

Further, the design of these neck gaiters does not contain the droplets and spread them. The other reason stated against wearing this mask was the material it was made out of. Gaiters are mostly made out of fleece.

These smaller droplets travel at faster rate than regular sized particles.

Studies showed that these were the least effective of all the above.


  1. The blood penetration resistance test- At a pressure of 120mm/hg
  2. Bacteria filtration efficiency- An efficiency of 95% is regarded best
  3. Particle filtration test- The bar is set at 0.1 microns / PM -O.1
  4. Breathability/ delta pressure test (4-5 mm H2O / cm2)
  5. Flammability test – Done at conditions that are cool, dry, and away from sunlight or moisture.

1.BLOOD PENETRATION TEST: In this test, we use a normal blood pressure of 120 mmHg of resistance. This is shot at the mask under controlled conditions. The idea behind this is, the mask should be resistant to fluids at this pressure and avoid penetration.

2.BACTERIA FILTRATION EFFICACY TEST: Basically done to find out how efficiently the mask can filter bacteria. So the passing minimum in this test is 95% and above. However many standard masks meet up to 99% efficiency in many countries.

3.PARTICLE FILTRATION TESTS: This test checks the filtering capacity of the mask in terms of the size of the particle. And again the passing minimum is about 0.1 micron.

4.BREATHABILITY OR DELTA PRESSURE TEST: Here, in simple words, we check the ability of the mask to allow adequate breathing and make it easier to wear for long hours. The recommended pressure is 4 to 5 mm H2O/cm2. The pressure difference should be within the normal limits to pass this test.

5.FLAMMABILITY TEST: It’s just a test that checks if the mask does not catch fire or doesn’t spread any flames.

It is important that the masks meet all these standards or exceeds them to be termed ideal or effective.


If in doubt, go for these simple steps while choosing a mask.

  • 1st layer or the outermost layer: The outermost layer should be water-repellant if possible.
  • 2nd layer or the middle layer: The middle layer acts as a filtration layer.
  • 3rd or the innermost layer: This layer should be capable of absorbing moisture.


Always remember to store your mask in a cool, dry environment away from sunlight or moisture.

This may promote the growth of fungus or other organisms and further worsen the situation.


It is advisable to change your mask once it becomes moist from constant use or from coughing or sneezing.

Disposable masks should be properly disposed off after the intended period of usage. (approximately 8 hours at a stretch).

Never store used masks in your bags and re-use it.


  • It is a good thing we choose to wear a mask. However, it is equally important to wear them properly.
  • A mask should be well fitted
  • It should cover the nose and the mouth properly.
  • Masks can only be effective with proper hand-washing and maintaining the proper distance from others (minimum of 6 feet). Either use soap and water to maintain hand hygiene or use alcohol-based hand sanitizers. Therefore, clean your hands before touching a mask.
  • Check the mask for any potential damage (bends, tears, etc.,).
  • Figure out the proper way to wear them, by checking the inside and the outside. The outside is usually darker and has a metal strip over it.
  • Pinch the metal strip against your nasal bridge. This moulds the mask against your nose and offers good coverage. Then gently cover the nose, mouth, and chin.
  • While wearing the masks do not manipulate them. Never touch the outer surface of the mask. If touched accidentally, be sure to wash your hands.
  • Removing the mask is also important. Use the suspension elastics that go behind the ear to remove them.
  • Be sure to properly dispose off them in a closed bin. Wash your hands thoroughly after disposing.
  • Remember, while using poly cotton masks be sure to wash them regularly at atleast 60 degrees after every use.
  • However, the best way is to remain bound at home to reduce the spread of the virus and avoid getting contaminated by one.

Finally, it is important to understand that, ‘something is better than nothing. Pick a mask that suits you the best and keep wearing them. It is not okay to avoid personal protection after your COVID shots. Continue wearing your mask even after taking the vaccination.

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Dr Kavitha M

I am an undergraduate degree holder in dentistry. I have a great interest in music and reading. I am a linguaphile. My areas of interest lie in psychology, medical imaging, diagnostics, and oncology. I am a person who focuses more on the emerging areas of forensics.


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