Using half-facepiece respirators for H1N1.

A respirator is a device designed to help provide the wearer with respiratory protection against inhalation of airborne contaminants. Increasing the filtration level of a particle respirator does not increase the respirator's ability to reduce a user's exposure to contaminants. The APF of a respirator, which is affected by the respirator style, determines the potential for exposure reduction. Surgical masks that are not approved as filtering facepiece half-mask respirators do not have an APF and should not be used for reducing workers' exposures to particles in the air.