What is the function of air-purifying respirators?

• A. They ventilate a room.
• B. Gas masks that filter or clean some chemical gases and possibly particles.
• C. They supply clean air from a tank.
• D. They create positive pressure in the suit.

Answer: (B)

Air-purifying respirators work by removing contaminants from the air you breathe through filters or chemical cartridges. They scrub out or adsorb certain chemical gases and, in some cases, particulates, so the air reaching your lungs is cleaner in contaminated environments. They don’t ventilate a room or provide air from a tank—that would be a ventilating system or a supplied-air respirator. Some powered versions can create a slight positive pressure inside the hood, but that’s a byproduct of the continuous flow of filtered air, not the primary purpose. So the main function is to filter or neutralize contaminants in the ambient air before you inhale.