Which statement about respirator classifications is correct?

• A. Respirators are categorized into air purifying and air supplied.
• B. An air-purifying respirator provides clean air from an independent compressed air supply.
• C. All respirators require the same level of fit testing.
• D. Negative pressure respirators do not require any testing.

Answer: (A)

Respirator classifications revolve around how breathing air is provided. They are grouped into air-purifying and air-supplied types. Air-purifying respirators clean the air you breathe by filtering or absorbing contaminants from the ambient environment using cartridges or filters. They rely on the air in the surroundings, so their effectiveness depends on the contaminant levels and the filter chosen. Air-supplied respirators, on the other hand, deliver clean breathing air from an independent source outside the wearer, such as a hose from a compressor or a backup air tank. This makes them suitable for environments where the ambient air is unsafe or lacks sufficient oxygen.

The statement that best captures this distinction is that respirators are categorized into air-purifying and air-supplied. The other ideas misstate how these systems work: filtering or purifying air does not mean the device provides air from an external supply, and fit-testing requirements vary—tight-fitting respirators require fit testing, while some loose-fitting configurations do not. In all cases, safety procedures require proper selection, usage, and verification of fit where applicable.