A single CBD Armour Respirator mask with red filter

Standard, surgical, or even homemade FFP2 respirators face masks. These words have invaded our day in the wake of the COVID-19 pandemic. As physicists, it is not up to us to make recommendations on their use to minimize the risk of contagion. 

However, we can provide information about the mechanisms involved in its operation. Many may think that these devices act primarily as a sieve. But nothing could be further from the truth.

Do You Know How Respiratory Protection Face Masks Work and which Respirators to Wear?

When we sneeze, cough, or simply speak, we produce aerosols. These are the particles of several sizes that accompany the exhaled air. 

These are generally water droplets between 1 and 100 microns, which evaporate rapidly and can release bacteria and viruses into the air. 

In a pandemic situation, the air can be filtered through a face mask to protect the wearer and respiratory system from these pathogen-laden aerosols. The first filtering mechanism that comes to mind is that of a sieve: as in a kitchen strainer, only particles smaller than the holes would pass through the face mask!

However, basing a filter on this principle has a drawback: the smaller the holes, the better the filtering, but the more difficult it becomes to breathe through them. 

In order for the mask to be used without mechanical assistance, it is necessary to avoid a filter with submicron holes, which would be necessary to block bacteria and viruses. Fortunately, other mechanisms are involved in the process to trap particles of all sizes.

Which Respirators Provide Protection Against Coronavirus?

There are two types of devices such as:

  • Surgical Masks

On the one hand, there are surgical masks, whose main purpose is to prevent the large particles emitted by the wearer, such as saliva droplets, from dispersing to the environment. 

These masks do not seek to filter the small particles present in the air. In fact, their efficiency in this regard isn’t that good.

  • Protective Respirators or FFP Masks

Another type of device is a "protective respirators". These receive the generic name of FFP (Filtering FacePiece), which is accompanied by a number indicating the degree of filtering. 

These respirators are designed to filter the air and reduce the number of particles and germs that the wearer breathes in.

For example, the FFP2 and FFP3 masks, respectively, filter 95 and 99 percent of particles with a mean diameter of 0.06 microns. This requires a snug fit to the face, which is usually accomplished with two rubber bands around the head and a nose clip.

FFP2/N95 and FFP3/N99 are the most widely used personal protective equipment (PPE) in the health field to prevent the spread of infectious diseases. 

Their nomenclature determines that they filter up to 95% and 99% respectively of the elements in the air. However, they are not resistant to oil and other liquids. They can be of two types, with or without a filter mask.

The importance of N95 and N99 masks is that they create an airtight seal against the skin. This prevents the passage of airborne particles, including pathogens. 

Its effectiveness has been tested against particles up to 0.3 microns in diameter. 

Although coronavirus particles measure between 0.05 and 0.2 microns, they are generally transmitted by respiratory droplets larger than 5 microns. And, by direct contact with infected secretions. 

So, in this scenario, these masks do work as a preventive barrier.

Final Thoughts

Wearing a mask is an essential precaution to protect ourselves from COVID-19. But for those who are more prone to infection, they need a higher level of protection. Respirators can provide that! 

We hope you enjoyed our guide for a detailed overview of how respirators work and which one is best for you!