The availability of approved surgical N95 respirators becomes limited during disease outbreaks, the U.S. Centers of Disease Control and Prevention (CDC), the European Center for Disease Prevention and Control (ECDC), and the World Health Organization (WHO) recommend respirators at least as protective as an N95, filtering facepiece (FFP2), or equivalent particulate respirator, and the CDC indicates that reusable respirators and powered air purifying respirators (PAPRs) should be used where feasible.
During the COVID-19 pandemic, the CDC published tiered recommendations in their February 2020 “Strategies for Optimizing the Supply of N95 Respirators.” Under the conventional capacity strategies, CDC indicates that “in times of shortage, only health care personnel (HCP) who are working in a sterile field or who may be exposed high velocity splashes, sprays, or splatters of blood or body fluids should be provided the surgical respirators. Other HCP can use standard N95 respirators.” CDC goes on to say, “Use alternatives to N95 respirators where feasible. These include other classes of filtering facepiece (FFP) respirators, elastomeric half-mask and full facepiece air purifying respirators, powdered air purifying respirators (PAPRs) where feasible. All of these alternatives will provide equivalent or higher protection than N95 respirators when properly worn.”
Filtering facepiece respirators (FFR), or respirators, similarly offer a balance of filtration and breathability; however, whereas medical masks filter 3 micrometre droplets, respirators must filter more challenging 0.075 micrometre solid particles. European FFRs, according to standard EN149, FFP2 respirators filter at least 94% solid particles and oil droplets, and US N95 FFRs, according to the U.S. National Institute for Occupational Safety and Health (NIOSH) 42 CFR Part 84, filter at least 95% particles.
In the update on June 2020, WHO recommended that a particulate respirator at least as protective as NIOSH certified N95, N99, US FDA surgical N95, European Union standard FFP2 or FFP3, or equivalent, should be worn in settings for COVID-19 patients where aerosol generating procedures are performed.