CARBON DIOXIDE SENSOR

A carbon dioxide sensor has a first electronically conductive metallic base member, an electrochemically active region of a continuous glaze of pH sensing glass in electrical contact with a portion of the base member, a second electronically conductive metallic base member, a second electrochemically active region of silver and silver halide in electrical contact with the second base member, a first layer of electrical insulation disposed between the first and second base members, a second layer of electrical insulation disposed over the second base member, an immobilized electrolyte contacting both electrochemically active regions, and an outer sheath of carbon dioxide permeable, ion-impermeable diffusion barrier material encapsulating at least the electrochemically active regions and the electrolyte.