During expiration. the carbon dioxide (CO2) levels inside the dead space of a filtering facepiece respirator (FFR) increase significantly above the ambient concentration. To reduce the CO2 concentration inside the dead space. we attach an active lightweight venting system (AVS) comprising a one-way valve. https://www.roneverhart.com/Pitkin-Ave-east-toward-Stone-Avenue-Brownsville-Mother-Gaston-Blvd-1964/