Face Mask Definitions & Considerations
Brief Introduction to the Origins of Face Masks
Evidence of face masks can be traced all the way back to Renaissance paintings in the 1700s. Before we understood that pathogens could be airborne to spread disease, facial masks were originally worn to reduce smell. It was first-believed that contagions such as the bubonic plague spread because the atmosphere was contaminated, not from person to person exposure.
Facial coverings have evolved in design and usage scenarios over time. In 1897, two German scientists named Carl Flügge and Jan Mukulicz-Radecki were able to prove that pathogens existed in respiratory droplets and the use of surgical masks to prevent the spread of disease was born. During the 1970s, N95 respirators with valves were invented to meet an industrial need in coal mines and factories.
The valve was designed to prevent factory workers from breathing in harmful matter or dust that could be generated from activities such as mining, sanding, or sawing. N95 masks with valves operate in a one-way capacity meaning they protected the miners from inhaling harmful particles, but the air that miners exhaled back out was not filtered at all. With the rise of the AIDS pandemic and the spread of the tuberculous in the 1990s, the CDC created guidelines around the use of personal protective equipment (PPE), by healthcare professionals.
Once it was discovered that tuberculous is highly contagious through respiratory droplets, the CDC placed particular emphasis around creating respirator standards for PPE. The CDC began recommending that healthcare professionals wear N95 respirators without valves so that both the air that is inhaled and exhaled is filtered which is still the type of respirator that is recommended today.
Common Types of Face Masks Explained
Although mask applications have fluctuated throughout history, most modern-day facial coverings worn in 2020 are donned for the purpose of reducing the transmission of viruses. Surgical masks, KN95 masks, N95 respirators, and homemade facial coverings vary in construction and the degree to which they filter out liquid droplets and/or airborne particles.
Viruses can live outside the body for varying amounts of time depending on environmental conditions such as temperature, the type of virus, and the type of surface. Although initial reports have found that COVID-19 can live on certain surfaces for up to three days, the CDC has said person-to-person contact is likely the primary way the virus is spread.
When people are within six feet of one another the virus can be spread through respiratory droplets if an infected individual coughs, sneezes, or even talks. Current CDC guidelines recommend that vigilant hand washing and socially distancing are the best lines of defense for the general public to slow the spread of germs. Some studies indicate that the virus can be spread even by people who do not exhibit symptoms.
For the foreseeable future, some type of facial covering is advised any time people are unable to avoid staying at least six feet from each other outside their homes. Many states such as Connecticut, New Jersey, and New York, now require that all individuals wear facial coverings when in public. Violators can face up to a $1,000 fine or other repercussions. Exact mask regulations vary from state to state so everyone should check with their local government for more information.
N95 respirators are a type of personal protective equipment that have a minimum of 95% efficiency in filtering out toxic matter such as dust, liquid droplets or airborne particles. These types of masks mean that contaminants bigger than 0.3 microns cannot pass through the nonwoven fabric of the mask. One micron, short for micrometer, is equal to one millionth of a meter in size.
One millionth of a meter is also equal to about .00004 inches. To put that in perspective, bacteria averages about 10 microns, dust ranges anywhere from 2 to 10 microns, and pollen is typically 10 microns or more. Once you have a visual for the size of micrometers, it makes sense how respirators that filter out anything bigger than 0.3 microns can be used in a variety of settings and applications.
The letter “N” in N95 stands for “Non-Oil” which means that the mask is suitable for any environment where oil isn’t present. N95 masks can be used in industrial settings such as sanding to prevent dust inhalation, or in healthcare applications to prevent inhalation of aerosolized contagions.
Respirator regulations vary by geographic region. When American made N95 respirators that have been approved by NIOSH (National Institute for Occupational Safety and Health) are in short supply, usage of respirators from other countries that perform similar rating standards are accepted as COVID-19 protection.
At this time, the CDC recommends against the average person wearing or purchasing traditional N95 respirators so that they can be reserved for the healthcare professionals that need them the most. K95 masks are an officially approved method to protect against COVID-19 and toxic airborne pathogens. Both K95 respirators and N95 respirators are tested to filter out 95% or more of airborne particles.
What Are KN95 Respirators?
K95 masks are the Chinese alternative to American rated N95 masks that are currently listed as a suitable alternative for COVID-19 protection according to the CDC due to mask shortages. The Chinese government certifies masks to particular standards under regulation GB2626-2006.
K95 respirators should only be purchased from trusted sellers as some K95 masks have been found to be counterfeit. The Massachusetts state website has started a running list of K95 mask manufacturers that were tested in America and found to have filtration efficiencies below the required 95%.
KN95 vs N95 Respirators
Both KN95 respirators and N95 respirators offer similar protection against airborne pathogens but N95 refers to the rating standard in the United States created by NIOSH and K95 is the rating standard used in China.
Sodium chloride (NaCl) is the test agent that is used as an aerosol during performance tests for both KN95 and N95 masks. Both masks also share a flow rate of 85 liters per minute.
What Are Surgical Masks?
Surgical masks are loose fitting face masks made of nonwoven fabric that have greater fluid resistance than woven fabric. Nonwoven fabric is made of short and long fibers that are melded together by heat or chemicals to create a uniform material. Felt and polypropylene are two examples of commonly used nonwoven materials.
Woven fabric such as silk or cotton is often woven on a loom by interlacing fibers which typically results in a stronger fabric, but the woven pattern allows for tiny holes that airborne particles can fit through. Surgical masks are often made of polypropylene which contributes to their fluid resistance capability. Since fibers are broken down and fused together to create nonwoven fabric, it is weaker than woven fabric, hence why surgical masks are typically recommended for single-use healthcare operations.
Surgical Masks vs. N95 Respirators
The primary difference between surgical masks and single-use N95 respirators are that respirators primary function is to reduce the wearer’s exposure to airborne particles whereas surgical masks are designed to prevent the wearer from ingesting respiratory droplets via their mouth or nose.
The mask wearer is protected from respiratory droplets expelled by other people or patients, and other people are also protected from any large droplets expelled by the mask wearer. Since surgical masks are loose fitting and do not contain a seal so they do not require fit testing or a seal check unlike NIOSH approved N95 respirators.
Facial coverings is a generic term referring to any cloth mask that snugly fits on the face, covers the ears and mouth, and can be secured with ties or loops. Current CDC guidelines state that all American citizens should wear face masks in public, particularly when social distancing measures of at least six feet between people cannot be maintained.
Due to a shortage of both N95 masks and surgical masks, many people have turned to homemade face masks to protect against the virus and comply with CDC guidelines. There are a few exceptions when people do not need to wear face masks. The CDC’s recommendation to wear masks does not apply to children under the age of two or people with certain health conditions such as breathing difficulties.
Exact mask regulations vary from state to state but many major retailers such as Costco now require both employees and shoppers to wear masks while inside retail locations.