Respirators are masks that filter and/or purify particles in the air. They are used in many different fields that are exposed to dangerous air particulates like dust, allergens, bacteria, viruses, and chemical fumes.
Respirators that are explicitly air-purifying are commonly called face filtering respirators (FFR). There are two separate accrediting bodies +that certify these types of masks.
NIOSH-approved respirators have their mark of approval, and the EN- certified marker is “CE” (Conformité Européen’).
Researchers Renegasamy, et al. did an independent laboratory assessment of eight models of NIOSH-approved N95 and P100 and CE-marked FFP2 and FFP3 respirators . They used methods similar to NIOSH respirator certification test methods to mimic the procedures for control. The research team concluded,
“Particle penetration data obtained in this study showed that the eight models of NIOSH-approved N95 and P100 and CE-marked FFP2 and FFP3 respirators used in this study provided expected levels of laboratory filtration performance against nanoparticles .”
That is to say, when respirators are properly certified and legitimately manufactured, they perform as they should. Not all classes of respirator masks work to the same degree of purification, but it is important that they are properly certified.
The classification of respiratory face masks is important to understand. When people like healthcare workers cannot get adequate protection from a mask it can have major adverse effects.
Surgical masks block large particles like droplets, splashes, and sprays that could contain chemicals, viruses, or bacteria. These masks cover both the nose and mouth but are mainly constructed of a three-ply fabric. They do not form a tight seal against the face. Surgical masks do not offer protection from airborne infectious diseases.
It is still beneficial to block possible large droplets as a means of spreading bacteria and viruses, however, a surgical mask only blocks 0.04 to 1.3𝜇m sized particles. That is eight to twelve times less than an N95 mask. Lee, S. A., et al. note that both surgical masks and N95 masks have been found to be equivalent in blocking low concentrations of the influenza virus . The researchers note that.
“[Surgical masks] have been cleared by the Food and Drug Administration for sale in the US, while, in the UK, they must first comply with the Medical Devices Directive (MMD 93/42/EEC) and be CE marked. However, because N95/FFP2 respirators or above may be in short supply during a pandemic—or not available in many countries—it is important to know the protection efficiency of surgical masks .”
According to Lee, S. A., et al. , “NIOSH-approved N95 filtering facepiece respirators or higher are recommended for healthcare workers against airborne infectious diseases such as Ebola.” But how can you tell which type of mask provides that level of protection?
Respirators and masks have special codes that are used for their names and are printed on the masks or packaging. NIOSH and the European Standard use different codes that correspond to different levels of protection. Here is a summary of those codes and what they mean:
NIOSH classifies particulate filtering facepiece respirators into nine categories: N95, N99, N100, P95, P99, P100, R95, R99, and R100.
The European Standard classifies FFRs particulate filtering facepiece respirators into three categories: FFP1, FFP2, and FFP3.
FFP2 respirators are approximately equivalent to N95 respirators. They are recommended for use in preventing airborne infectious diseases in the US and some other countries.
FFP3 respirators provide the highest level of protection and are the only respirator acceptable for protection against infectious aerosols in healthcare settings in the UK.
Currently, The Centers for Disease Control and Prevention (CDC) and the UK Health and Safety Executive (HSE) advise the use of N95 or higher respirators and FFP3 respirators against airborne infectious diseases in healthcare settings. Lee, S. A., et al. suggest that surgical masks may be an option when these respirators are scarce .
The CDC explains that individual filtering facepiece respirators are required to have the following markings:
The COVID-19 pandemic has taken the world by storm. High rates of hospitalization mean that protective equipment like masks is in short supply for healthcare workers. On April 3, 2020, the CDC added language to the FDA’s Emergency Use Authorization (EUA) to respond to the crisis.
In this language, the CDC authorized additional N95 respirator alternatives. This applies to certain NIOSH-approved respirator models to be used in healthcare settings. They also temporarily suspended the need to perform fit tests when issuing employees' respirator masks.
The CDC’s EUA plant breaks down responses by capacities. There are three levels of response: surge capacity, conventional capacity, contingency capacity, and crisis capacity.
There are no distinguished criteria for “surge capacity,” however, it is generally marked by an approaching decrease in N95 mask supplies .
“The ability to manage a sudden, unexpected increase in patient volume that would otherwise severely challenge or exceed the present capacity of a facility .”
During surge capacity, steps are taken to conserve the use of N95 respirators and prioritize their use to the people that need them most .
When there is not any additional need for N95 masks, they are said to be at conventional capacity . During times of conventional capacity, all of the normal rules for mask use and types of masks that can be used apply without exception. In times of conventional capacity, there is no strain on the N95 mask supply chain and they are readily available for use and purchase.
When daily standard practices need to be changed but there will be no impact on patient care or worker safety, contingency capacity measures are applied . These practices are temporary measures for periods of expected N95 respirator supply shortages.
When supplies of N95 respirators are known to be low, crisis capacity measures come into play . During crisis capacity, strategies of protection may be taken that would not normally be acceptable with US care standards. Such is the case with the COVID-19 crisis and the need to use alternatives to the N95 respirator.
Healthcare facilities are authorized to use NIOSH-approved alternatives during the COVID-19 pandemic . These alternatives include other classes of filtering facepiece respirators, elastomeric half-mask and full facepiece air-purifying respirators, powered air-purifying respirators (PAPRs). Certified NIOSH equipment lists can be viewed online.
“Every other NIOSH approved filtering facepiece respirators is at least as protective as the N95. These include N99, N100, P95, P99, P100, R95, R99, and R100. Many filtering facepiece respirators have exhalation valves and should not be used in surgical settings as unfiltered exhaled breath would compromise the sterile field. On March 2, 2020, FDA issued an Emergency Use Authorization (EUA) authorizing the use of certain NIOSH-approved respirator models in healthcare settings .”
N95 masks filter at least 95 percent of particles that are 0.3 microns or larger . NIOSH, under the CDC, approves N95 masks. When it comes to KN95 masks, they are regulated by the Chinese government. Their performance is almost identical to that of the N95 mask with minor differences in their specifications.
The FDA has issued an emergency use authorization (EUA) for KN95 masks, and the CDC lists KN95 masks as a suitable alternative when N95 respirators are not available . The FDA is willing to authorize KN95 masks as long as they meet the criteria for documentation and authenticity.
Still, Chang, K.  for the New York Times reports that hospitals are reluctant to order KN95 masks amid uncertainty that they will be successfully delivered. Hospitals are also disinclined to take on the liability of masks potentially being counterfeit. While the FDA is taking steps to help guarantee authenticity, it is still a risk that hospitals are not comfortable taking on.
According to a January 2020 3M Technical Bulletin ,
“China KN95, AS/NZ P2, Korea 1st Class, and Japan DS FFRs should be considered as ‘equivalent’ to US NIOSH N95 and European FFP2 respirators, for filtering non-oil-based particles such as those resulting from wildfires, PM 2.5 air pollution, volcanic eruptions, or bioaerosols (e.g. viruses).”
If a Chinese KN95 manufacturer has submitted all necessary documentation, the FDA may issue their certification. This FDA certificate means that the company’s KN95 mask complies with the emergency use authorization (EUA). Importers can request this certificate from the Chinese manufacturer. While there is concern over counterfeit documentation, there is little that can be done to provide certainty.
Ultimately, the consumers of KN95 masks and non-NIOSH-approved alternatives must be willing to accept a degree of uncertainty as a lesser risk than not having the respirators. Importers can do their best to verify mask markings and certifications but with many counterfeit foreign products, it can be almost impossible for retailers to guarantee legitimacy.
Finally, it is important for the public to understand their duty to reserve N95 masks for the healthcare industry. It has been advised that the general public wears masks, such as surgical masks and homemade face coverings to help prevent the spread of the COVID-19 virus.
Those with cases of COVID-19 in their homes face a greater challenge. Not all cases are being hospitalized or tested, so those who are not in need of hospitalization are waiting out the course of the illness in-home quarantine. N95 respirator alternatives could be especially helpful to these individuals who are trying to prevent the spread of COVID-19 within their homes and families.