Which statement about air-purification respirators is correct?

• A. They provide their own oxygen supply
• B. They can be used in oxygen-deficient atmospheres
• C. They do not require any oxygen
• D. They are suitable only when there is adequate oxygen

Answer: (D)

Air-purification respirators clean the air you breathe by filtering contaminants; they do not add oxygen. They rely on the oxygen present in the surrounding environment. In environments with insufficient oxygen, these respirators can’t protect you because you could inhale hazardous contaminants while the available oxygen is too low to sustain life. That’s why they’re suitable only when there is adequate oxygen. If the atmosphere is oxygen-deficient, you need a respirator that supplies air or oxygen, such as a supplied-air respirator or an SCBA. The statements claiming they provide their own oxygen, can be used in oxygen-deficient atmospheres, or do not require oxygen are not accurate.