Abstract: A respirator comprising a facepiece having a cup shaped portion for sealingly engaging a face of a wearer and covering the mouth and nose of the wearer and a cover having a cup shape that is complementary to the cup shaped portion of the facepiece. The cover is capable to detachably mate with the facepiece to define with the facepiece a void area that is cup-shaped and suitable to receive a filter having a complementary shape. The filter includes an apex portion, a side portion depending from the apex portion and a continuous flange portion surrounding said side portion and projecting laterally therefrom.