A powered, air-purifying respirator (PAPR) is a type of personal protective equipment used to safeguard workers against contaminated air. PAPRs consist of a respirator in the form of a hood, or full-face mask, which takes ambient air that is contaminated with one or more type of pollutant or pathogen, actively removes (filters) a sufficient proportion of these hazards, and then delivers the clean air to the user's face and/or mouth. PAPRs are sometimes called positive-pressure masks, blower units, or just blowers.