wicks dust mask P2

Understanding face masks – The best and Worst

In this article, I will go through the different types of face coverings, their ratings and appropriate use. I want to be frank with you and try to explain the many misconceptions and misunderstandings regarding dust masks, AKA ‘The FACE MASK’.

The reason why I feel this is important is that I read and see so many misinformed people online, giving their own uninformed opinion. If it wasn’t the fact that people are dying I would just let it lie.

My work involves the wearing of PPE, especially dust masks. Some dust including Oak is a carcinogen so I have to take extra special care. Understanding what mask I should be wearing is extremely important if I am to protect myself from inhaling potential toxins. 

I have extensively researched this topic from respected sources such as the CDC and the WHO. So I can give you more technical manufacturer information I have turned to the major manufacturers such as 3M who supplies the NHS and other health services.

So what is a face mask?

A face mask is just a face-covering. It can be a disposable paper mask or a homemade cotton fabric mask. This is a basic description but there is more to know because of this current SARS-CoV-2 pandemic.

The face mask should be worn when you are in proximity of other people. Well, that is the ‘one shoe fits all’ approach, It is not that simple! I say other people because covering the face is a concept we embrace to protect others from being infected by us.  This is important for the obvious: saving of lives and protecting the NHS but also to reduce the R-Value by preventing the spread of the virus.

You will notice that I refer to these face coverings as:

  • Dust Mask
  • Respirator
  • Face Mask
  • PPE (General term for equipment design to protect the wearer) 
  • Face covering
  • Surgical Masks

All of the above describes what we see worn on the face by people for the prevention of foreign bodies entering our bodies.  

The Dust Mask

As the name suggests you can assume the mask is designed to prevent dust particle from entering the lungs or digestive system. Most of the commercially available masks are designed for trapping airborne particles.

The Respirator

Respirators are designed to fit tight to the face to prevent leakage. A Respirator can also be a dust mask as generally, they would be the same mask if they fit tight to the face. The respirator is also referred to as a ‘Negative-Pressure Respirator’.

What is a  Negative-Pressure Respirator?

If you exhale while wearing a respirator the air pressure inside the mask is less than the air outside the mask. The principle of Negative-Pressure only works if the mask is sealed to the face. Thus forcing the inhaled air through the filter. Remember our lungs is basically an air pump of high volume but low pressure (HVLP)

Thin poorly made budget face masks or surgical masks do not seal to the face so the air pressure is equalised when we inhale or exhale.

The Face Mask

Face masks seem to be herd adopted term for anything that covers the face. Before COVID was a thing you could do a search for ‘Face Mask’ and you get results for ‘Cucumber and Mint’ face packs but now you get a full array of fashion and PPE masks. Face masks are some form of face covering.


PPE is short for Personal Protection Equipment and is a general term. Any equipment or clothing designed to protect you from danger is considered PPE.

Face Coverings

The descriptive term known as a face covering can be anything that covers the face. A facemask can be as simple as a scarf or balaclava but mùany are making their own homemade face masks. Some are good and some are bad. These face coverings have very little protection by filtration but do help to protect others from water droplet carried viruses. The water droplets can be projected via coughs, sneezes or spit. The effectiveness of the face-covering is only as good as the fit. These have similar protection to a surgical mask.

Surgical Masks

Masks that are used by the surgeons are so the wearer does not cause infection to others. Surgical masks do not filter fine particles or virus but like homemade cotton face masks, they prevent infecting others. I would hope not to see a surgeon operating on me wearing a scarf or old bedsheet! Face masks protect others from infection. Surgical masks have no practical use by people working in construction or the manufacturing industry.

Surgical masks Versus Respirators

Respirators are a totally different piece of equipment compared with the surgical mask worn by medical personal. 

Respirators are designed to protect the wearer yet the surgical mask or face covering is for the purpose of protecting others. Respirators offer some protection to the wearer and if no valve is fitted, good protection to others. 

I hope you are finding this article interesting. We understand that not everyone’s experiences are the same so if you have something to add just leave it in the comments below.

Respirators with exhale valves fitted

You will notice that some masks have a plastic fitment. This small plastic device is a valve which allows breath to pass in one direction only. The valve allows the lungs to push our spent air out of the chest under no resistance. So the exhausted air is not restricted by the filter. The valve closes when the wearer inhales forcing the air to be breathed in to first pass through the filter material of the respirator or dust mask. 

Should these masks be worn by medical staff or carers

This is a matter of my opinion based on common sense. I feel any respirator or face mask fitted with a valve worn to protect others does little to prevent the spread of any virus. The reason for my analysis is that the virus is spread mainly via COVID infected moisture droplets. These droplets can also be an aerosol.

When droplets are sprayed by individuals these small globules of liquid is accompanied by moisture which is an aerosol (vapour). This aerosol is vapourised liquid from our lungs. The projected vapour or breath can also be the transport vessel of COVID-19. Watching medical professionals on our media wearing respirator masks (made by 3M amongst others) fitted with valves seems counterproductive or is it just placebo?

How a respirator valve works when you inhale

In my drawing here you can see the inhaled air which is depicted by the arrows is forced through the filter material. This is because the diaphragm valve is sucked closed as we inhale redirecting the airflow through the filter. 


How a respirator valve works when you exhale

This drawing demonstrates how the exhaled breath is not filtered when the mask has a valve fitted. When you exhale the diaphragm is pushed out of the way to allow your breath to pass unobstructed. Physics would expect our spent air to travel at more pressure which could propel the aerosol further. You could compare this with squeezing the end of a garden hose thus creating more pressure to spray water further.

Types of Face Mask

In my workshop, I wear a dust mask like the shaped ones you see worn in hospitals. There is a reason for this and that is those masks are not designed for hospital applications but for safe working practice in various industries.

These face masks are for the purpose of preventing particles from entering our lungs. The fine filter material can filter dust or other particles down to 0.3 microns.

What does the face mask categories mean?

You have probably heard the various standards being flaunted online and during the daily conference but they never explain what they are. 

USA face mask standards (NIOSH)

In the United States, they use the National Institute for Occupational Safety and Health (NIOSH) system of specification for face masks. This standard is recognised worldwide but some countries have their own standards although they are comparable.

The ‘NIOSH’ system

Examples of NIOSH:

Example1 N95: Not resistant to oil but 95% efficient at filtering particles down to 0.3 micron

Example 2 P100: Resistant to Oil and 100% efficient at filtering particles down to 0.3 micron

How is the NIOSH system worked out?

The NIOSH method of categorising is quite simple to understand. You remember me saying that these masks are principally designed for workplace PPE (Personal Protection Equipment)so don’t be surprised that they are designed for that. Manufacturing and construction was the primary user of face masks before this pandemic. Nurses and surgeons would normally wear a surgical mask which is designed to protect the patient, not so much the wearer which I will go into later. 

Respirator Oil resistance ‘Niosh’ is shown in the first letter N, R or P

  • N: Not resistant to oil
  • R: Resistant to oil
  • P: Oilproof

Respirator efficiency is measured as a percentage

Each of these categories of the mask is available in different particle trapping efficiencies. This efficiency is shown as a percentage of the effectiveness of the masks ability to trap particles down to 0.3 microns. 

  • 95: 95%
  • 99: 99%
  • 100: 100%

Types of dust mask in the UK and mainland Europe (Europe EN 149-2001)

The standards (Europe EN 149-2001)  are recognised in the UK and across Europe. Apart from the oil resistance that the NIOSH categorisation the P standards are similar. 

The categories as printed onto the mask or respirator itself is as follows:

  • FFP1 or FMP1(80%)
  • FFP2 or FMP2(94%)
  • FFP3 or FMP3(98%)


They are one and the same. The P is the important part which refers to the efficiency of the mask, for instance, P1, P2 or P3


FMP face masks are not used much as they are supposed to have limited reusability and we have cornered ourselves into a throwaway world of waste. I believe the FMP masks are not promoted as much as they should as the manufacturers want to sell limited life products again and again. So if you check your European face mask category printed on the mask you will probably see either FFP1, FFP2 or FFP3 and not FMP.

FFP2 or is the N95 better?

Both the FFP2 and the N95 are not resistant to oil but they have a similar efficiency percentage rating. You can assume that the NIOSH N95 respirator is comparable to FFP2.

Types of dust mask in Korea (Korea KMOEL – 2017-64)

  • KF80 (80%)
  • KF94 (95%)
  • KF99 (99%)

Types of dust mask in China  (China GB2626-2006)

Types of dust mask in Japan (Japan JMHLW-Notification 214, 2018)

Respirator filtration standards

Every filter requires some kind of filtration standard. The well-known face mask manufacturer 3M sets high yet achievable filtration standards. For instance, all 3M’s NIOSH standard respirators are capable of filtering particles down to 0.3 microns. The efficiency is measured in percentage. An N95 respirator can trap particles down to 0.3 microns and is efficient to 95%.

Materials used in the production of face masks

To put some perspective on this subject I will use surgical and N95 standard masks as an example. These masks are made by a variety of different manufacturers. 

Each manufacturer may use a different material for their brand of face mask. N95 is a standard which masks have to comply with if they are to meet the specification of said mask. So as long as the mask meets the standard it can be made from any material.

Fabrics used for the construction of face masks are chosen for a multitude of reasons.

  • Microstructure
  • Composition
  • Weave
  • Effective native mechanical filtration

Fabrics commonly used

Some manufacturers weave their own filtration material yet others buy standard materials. China has monopolised the global supply of filtration materials and face mask production. Since the supply of face masks is in high demand national companies across the world are looking into setting up their own face mask production. This production will require fabrics which are either bought from China or India. But if we are to centralise production we might need to weave our own filtration materials. The fabrics of 80 to 600 Thread count per inch.

Materials for face masks

  • satin (97% polyester and 3% Spandex)
  • cotton quilt, flannel (65% cotton and 35% polyester)
  • chiffon (90% polyester and 10% Spandex)
  • natural silk, Spandex (52% nylon, 39% polyester, and 9% Spandex)
  • synthetic silk (100% polyester)

These materials are not chosen, just because they are capable of filtering fine particles. It is also important that the materials are safe for air to be breathed through. For instance, a homemade face mask using a pretty printed cotton fabric might look nice but is the dye toxic to humans. Whatever you choose to wear close to your face you must be sure of its origins.

Face masks for Coronavirus

I want to be honest and clear with you with my explanation of the effectiveness of face masks during the coronavirus 2020 pandemic. This wasn’t the purpose of this tutorial but I believe it is likely the reason why you are here. I have been asked on numerous occasions lately about face masks and COVID-19 so I will try to answer them here. 

Should I wear a face mask

There are many factors that we must observe and use our common sense. But first I cannot stress enough that ‘Social Distancing’ is your best defence. I know there are times that you have no choice but to go out. Yes, you can perform the social distancing rule of at least 2m but accidents happen. 

Sometimes others are not so respectful and it could be too late to dodge them. If this happens you may wish you were wearing a face mask of one type or another. 

Can face masks protect me from the virus?

There is some debate that face masks could protect you from COVID-19. It is not that simple there are many things to consider. If you think of people as a herd you could have a strong case for wearing a simple surgical or homemade face mask. 

The principle is that if you are infected with the virus the face mask will trap the virus on the inside of the mask thus protecting others. If you can prevent the spread of the virus you will reduce the R-value to a level which reduces the risk of infection. The virus would eventually be eradicated.

Can Respirators protect me from Coronavirus

Respirators can trap particles down to 0.3 microns which is great for some bacteria and obviously great for dust. Coronavirus is only around 0.1 microns so it can pass through the filter. You would think that was the end for the respirator in regard to the virus. But the virus is transported between people (host) via water droplets and aerosol vapour. This moisture increases the size of the virus so it is possible that the filter could trap COVID. Also, the filter material is porous which can absorb the virus within its fibres. 

The risk to you for wearing the respirator

Think of the Respirator as a container which could collect the virus when you come in contact with infected people. It is wise to change the respirator whenever you believe you have come in contact with people or at least several times a day. 

Disposable respirators can collect moisture from your inhale and exhale. This will make it inefficient and restrictive and put unnecessary strain on your lungs.

Expertise, Authority and Trustworthiness

What is my experience in PPE?, My name is Marc Kett, a woodworker residing in France. I have for years been involved in serious PPE for me and my employees. Having a clear understanding of basic face masks and the more efficient respirators is an important detail, so I can make sure that I and my staff are protected. It is my responsibility. 

Reference sources I used for this article to enhance my own knowledge on this subject.

  • CDC (Centers for Disease Control and Prevention)
  • WHO (World Health Organisation)
  • 3M (Respirator manufacturer)
  • Worldometer
  • FDA (Food and Drug Administration)

2 thoughts on “Understanding face masks – The best and Worst”

  1. A lot of useful information that I’ve learned. Thank you so much for your article. I will keep an eye on your website regularly.

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Scroll to Top