Actually, I can give you a great deal of information on this.
Smoke inhalation isn’t just smoke in the throat. It’s also an irritation and searing of the very sensitive lung tissue. It is treated with oxygen because the very tender air sacks in the lungs can no longer expand as usual, which means higher oxygen concentrations must be fed to the cells that still can inflate and pull oxygen into the blood stream. The problem requires three things: things that suppress the inflammation response and therefore the buildup of fluid in the lungs, things that keep things sterile and prevent DNA repair issues, and things that assist healing.
Antioxidant rich foods (tea is one), natural antiseptics with the ability to assist in healing (honey is one), and proteins are what you need. More humid air may or may not help depending on the irritation you’re suffering. Mushrooms and certain herbs are known to reduce inflammation. Rest and lower amounts of movement can help, because the body is not exerting itself and therefore doesn’t need as much oxygen while healing.
I’d also recommend licorice.