| abstract |
A face mask is disclosed that can be reusable or disposable, and which filters particulate matter and noxious and poisonous gasses from breathed air. The mask has a mask shell that is thermoformed of cross-linked, closed-cell foam sheet that is impermeable to air while having good shape retention and elasticity. The mask shell is perforated with multiple holes in its central area to permit inhaled air to pass through the otherwise impermeable shell. This mask shell is stiff enough to support filter liners made of, for example, an activated charcoal impregnated fibrous sheet that covers the holes and is retained to the inside and/or the outside of the mask shell by a retainer which is easily removed to replace the filter liner(s). Alternatively, the filter liner(s) may be bonded to the inside and/or the outside surface of the foam mask shell to make a disposable mask. A one-way valve is mounted through the wall of the mask shell to exhaust exhaled air. |