What aspect of respirators is critical for their effectiveness?

The effectiveness of respirators hinges significantly on their proper fit on the user's face. A proper fit ensures that the respirator can create a tight seal around the face, which is vital for preventing contaminants from entering through gaps. If the respirator does not fit correctly, air can bypass the filtering material, rendering it ineffective in providing the intended protection against airborne hazards.

The necessity for a good fit is supported by the principle that without adequate sealing, even the best-quality respirators can fail to protect the wearer. This is why fit testing is an integral part of respiratory protection programs in healthcare settings, ensuring that individuals are wearing respirators that are compatible with their facial contours.

While the model, identification features, and materials of a respirator are important considerations, they do not supersede the need for a proper fit. A respirator could be the latest model equipped with advanced technology and made from high-quality materials, but if it doesn't fit the user correctly, its protective capabilities are compromised.