Conversion of nitrogen dioxide (NO

1. A system for generating a therapeutic gas including nitric oxide for use in delivering the therapeutic gas to a mammal comprising:

a pressure regulator diffusing gaseous nitrogen dioxide into an air flow wherein the air flow is configured to be between 5 to 60 liters per minute;

a receptacle configured to attach to the pressure regulator, the receptacle including an inlet, an outlet, and a surface-active material coated with an aqueous solution of an antioxidant, wherein the inlet is configured to receive the air flow and fluidly communicate the flow to the outlet through the surface-active material to convert the gaseous nitrogen dioxide to nitric oxide at ambient temperature.

2. The system of claim 1 , wherein the air flow is at 5 liters per minute.

3. The system of claim 2 , wherein the receptacle has a pressure drop of between 0.001 and 0.01 psi.

4. The system of claim 1 , wherein the air flow is at 60 liters per minute or lower.

5. The system of claim 4 , wherein the receptacle has a pressure drop of between 0.001 and 0.05 psi.

6. The system of claim 1 , wherein the receptacle comprises a cartridge.

7. The system of claim 1 , wherein the surface-active material is saturated with the aqueous solution of the antioxidant.

8. The system of claim 1 , wherein the surface-active material comprises a substrate that retains water.

9. The system of claim 1 , wherein the surface-active material comprises a silica gel.

10. The system of claim 1 , wherein the antioxidant comprises ascorbic acid.

11. The system of claim 1 , wherein the antioxidant comprises alpha tocopherol or gamma tocopherol.