A respirator is a personal device worn on the face that covers at least the nose and mouth and is used to reduce the risk of inhaling hazardous airborne particles such as dust and infectious agents or gases or vapors depending on the type of respirator. Respirators either filter particles from the air, chemically purify the air or supply clean from an outside source. Gas masks are “air-purifying respirators” which include a facepiece and cartridge or canister, which may also filter out particles. Different cartridges are available depending on the type of hazard. Airline respirators use compressed air from a remote source and a self-contained breathing apparatus (SCBA) includes an air supply. SCBA respirators are commonly used by firefighters, weigh 30 pounds or more and requires special training to use.
In particulate respirators, filtering facepiece materials may be silicone, neoprene or rubber. Particulate respirators may be completely disposable, such as an N-95 respirator. These types of respirators are given a 95, 99 or 100 rating when they are shown to filter out at least 95%, 99% or 99.97% of airborne particles during “worse case” testing with a “most penetrating” sized particle. Since industrial oils can degrade the performance of the filter, respirators are rated on oil resistance where N is Not resistant to oil, R is somewhat Resistant to oil and P is oil Proof. The National Institute for Occupational Safety and Health (NIOSH) is the Unites States federal agency that approves respirators for occupational uses.
Reusable or elastomeric respirators have a facepiece that is cleaned and reused and filter cartridges that are discarded and replaced. Powered air purifying respirators (PAPRs) have a battery-powered blower that moves air flow through the filters.
Although N95 respirators are disposable, shortages of N95 masks due to increased demand during the COVID-19 pandemic led to research into methods for decontaminating and reusing N95 masks Potential methods for decontamination of N95 masks include ultraviolet germicidal irradiation (UVGI) and hydrogen peroxide vapor.