Introduction 

The global COVID-19 pandemic has brought the N95 mask or respirator into common knowledge. A type of mask which completely seals off a person’s face and nose from the outside environment, the N95 respirator has been widely used by medical professionals who need to both protect their patients and themselves from airborne particles associated with the coronavirus.

They recently gained a lot of attention because due to their effectiveness in protecting wearers, there was a large shortage of these types of masks, making it difficult for those on the frontlines treating people with this virus to be able to attain them. As a result, some restrictions were applied to make sure that they were only to be used by medical professionals.

However, these masks have existed for some time; they did not appear out of thin air when COVID-19 became a global issue. This article will discuss some of the background surrounding N95 masks or respirators, including their history, and the sorts of environments for which they were designed to be used.

What is an N95 Mask and what does it do?

Before we get into the background, it is important to understand the nature of the N95 respirator, and what it is specifically designed to do, and to be able to differentiate it from several other types of masks.

The N95 is a disposable mask which is often (though not exclusively) shaped like a shell, which fits closely, and presses up against the face of the wearer. The fit should be snug, and no air should be able to pass through the edges of the mask.    They are affixed to the head of the users through two straps, which are worn over the back of the head. A good N95 mask should have a snug fit and force all respiration (aka breathing) through the front of the mask.

The N95 respirator should not be confused with surgical masks, which are much looser fitting fabric masks, which are more generally used to protect others from liquid or vapor droplets caused by breathing, coughing, or sneezing. Surgical masks have a lower standard of requirements, and as a result are easier to breathe through; much air can be inhaled through the edges of the mask. As a result, they do not necessarily protect the wearer from airborne droplets.

N95 Requirements

While they may appear to be paper, they are in reality made up a mesh of synthetic non-woven polypropylene fabric. To be certified within the U.S. they must be able to filter out at least 95% of any airborne particles. The N95 is not considered to be resistant to oils (for this requirement would require a different type of mask or respirator, known as the “P95.” We will not be discussing these in this article; this is mentioned merely for comparison purposes).

According to the Food and Drug Administration (FDA), the designation “N95” refers specifically to the fact, that when tested, a respirator will be able to block at least 95 percent of particles at a size of .03 microns.

Due to various shortages, as well as various other factors (such as being healthy enough to breathe through the restriction created by these masks), employees should be cleared by a medical professional before wearing respirators, which  are designed to fit closely to the face. This should be extended to include surgical N95 masks (a subset of N95 masks which also protect against exhalation as well as inhalation). To properly wear an N95 mask, it must be fitted to a specific user.

To be able to effectively wear an N95 mask, the user should ideally have no facial hair (which causes the inability for the mask to attain a fit against the skin of the wearer)

N95 masks are designed to be disposable and are single use devices. The way that these masks work is that they become more efficient the longer they are worn; they pick up more and more particles in the environment, and further restrict air movement. The reason why they are not to be worn for too long is because of this efficiency. Over a period of time, due to this accumulated sediment, it becomes more difficult to breathe through them. 

Because of this, the ideal amount of time that is recommended for wearing an N95 respirator is approximately 8 hours. For periods of time longer than this, the respirator becomes “full.” As these are designed a little differently than earlier masks, they do not respond well to being washed out and worn again, so they must be discarded.

To reiterate, the longer the period for which an N95 respirator is worn, the more particles it filters out through the air. The addition of more particles into the mask add to the filtration ability; there are more things in the mask that serve as blocking mechanisms. Unfortunately, while this should theoretically make the masks more efficient, they no longer are healthy for a person to wear because of the difficulty caused for breathing. This is particularly true if one is dealing with dry physical particles, such as in dusty environments; the masks or respirators become clogged, causing problems for the respiration of the user. In medical environments, while there may not be as much dry physical material, the build up in potentially contagious bacteria can make the masks themselves unsanitary.

History

To get a clearer understanding of the background of the N95 mask, let us spend a little time going over the history of masks themselves. 

Origin of Masks

The use of masks for protection against disease goes back to the medieval era, during the time of the Black Plague. Masks at this time were designed specifically to protect against smell. This is depicted in many paintings from the era, showing them being used by gravediggers to protect against the stench caused by the bodies which needed to be disposed of as a result of the plague. It was commonly believed at the time that disease itself was spread by noxious odors.    While we now know that the plague itself was caused by insect bites from rats who were exposed to the disease, at the time, there was the belief that the smell was what caused the infection. 

As a result, masks were used to protect the wearer against the smell of those who were infected. The bird-like masks that doctors wore during this era were designed to have a cavity to place incense to protect the wearer against the smell.  This was believed to protect the wearer against the infectious nature of foul odors.

Discovery of Bacteria

In the late 19th century, researchers first began to understand the existence of bacteria, and the field of microbiology was developed. The first surgical masks began to be worn in 1897.  The masks that were worn were made out of cloth fabric. Much like modern surgical masks, they were not designed to protect the wearer against airborne illnesses; they were more designed to prevent the spread of bacteria to patients. This helped prevent doctors from coughing or sneezing into open wounds during surgery causing further infections to those who were already in a weakened state.

The creation of Respirators

While previous masks were designed to protect patients from exposure, they did not work well to protect wearers against infection. When it was discovered that most infections were spread by airborne bacteria instead of through fleas (which was the current operant theory), a mask was created which was securely adhered to the face of practitioners, and was made from multiple layers of gauze and cotton. This mask, created by Dr. Lien-teh Wu, was a medical breakthrough, which reduced infection in doctors significantly. As it was created from inexpensive materials that were easily at hand, this made it possible to create these respirators, which then became used heavily within medical populations.    They were also adopted by the military, and many soldiers would use them to help protect against chemical attacks. 

This same mask also became heavily adopted during the Influenza epidemic of 1918. From that point on, this approach was used for protection against the spread of infection in many environments.

N95 Respirators

The  N95 respirator was not originally designed for medical purposes. They were created for mechanical and industrial use, as they served well at protecting from many different types of airborne particles from entering the lungs of the user.

Previous devices were designed for miners to protect them against black lung disease. These older masks were much larger and clunkier; they look more like the “gas masks” that one might associate with use in World War I and II to protect wearers against chemical warfare. 

However, as the technology progressed, respirators were designed to be much lighter and easier to use. 

The modern N95 mask was officially approved on May 25, 1972 and was descended directly from Wu’s invention. It was relatively lightweight and easy to wear. The new N95 mask was designed as a single use device, which were created using melted polymers that were blasted by air to create miniscule fibers.   The design was so that when exposed to small silica particles, vapor, or viruses, these foreign substances would become caught in a complex maze of these fibers. These were originally created by the 3M corporation, who also added electrostatic charges to the materials within the mask, which would serve as a way of magnetically pulling in even smaller particles, thus increasing the effectiveness of the respirator. 

These new N95 respirators became popular for use in industrial occupations, ranging from construction, mining, and painting. They were not originally adopted for medical use, largely because they were designed to protect the wearer, and not necessarily patients. It was until modifications came to the mask to create the surgical N95 masks that they began to be adopted for medical use, which were also designed to reduce the amount of materials produced through exhalation from reaching the exterior environment. 

In fact, the medical use of the N95 mask did not occur until the mid-1990s for use at reducing the spread of a rapidly growing drug-resistant strain of tuberculosis.    They became commonplace in China, during the SARS outbreak in the early 2000s. The public also began wearing them in areas with high levels of air pollution, such as in Beijing.  

In what Professions are N95 masks typically used?

Contrary to popular belief, the N95 mask is only rarely used in hospitals, except for instances where there is a disease outbreak. This is because they are somewhat expensive and are designed only for single use.

As mentioned earlier, they are used in many industrial fields, such as mining, or in automotive factories, where there is a high risk of contamination from airborne particles. Carpenters have also been known to make use of N95 masks to help protect against inhaling of sawdust, sheetrock, or other airborne particles.

They are now also being used commonly among those who work with nanotechnology, as has been recommended by the National Institute for Occupational Safety and Health (NIOSH). However, there are some limitations associated with this use, as there is the risk of particle leakage due to poor fits where there may be a gap between the face of the user and the respirator.   Nanotechnology particles can easily find their way around the edges of the devices. This is especially likely in the case of half-mask respirators such as the N95.

However, the most common uses for respirators such as the N95 remains protection against dust or paint vapors. Anti-dust respirators (particularly the regular N95) is used in 19 out of 20 workplaces where respirators are regularly used. 

The use of the N95 mask has remained popular in many medical professions, particularly those which may be exposed to bacteria. They are commonly used by dentists and dental assistants, not only because of the likelihood of coughing or sneezing from patients, but also because of the likelihood of fluid at high pressure, such as in many  cleaning and irrigation tools commonly used in dental practices.

Final Thoughts

While the N95 mask or respirator is now commonly associated with medical protection against the COVID-19 coronavirus, their use is still considerably widespread in many other fields and professions. While there are numerous restrictions that have been applied to the use of these respirators due to global shortages, the need for these devices in other areas still remains.  


If one wishes to purchase N95 respirators online, on the Clinical Supplies USA website.