Hi Mb339, Buzz here. I haven't used that Ram air button either. but it opens up an airscoop near the LH air cond pack ram air inlet and permits ram air to enter the air cond distribution ducts.
I imagine you'd only use it on warm days, low altitude , to clear too much cigarette smoke from the cabin (grin). I don't think it's enabled when the airplane is pressurized. Airbus must have worried about oil fumes from the engine bleed air supply. We get some oil fumes from the APU every so often (bad oil seals) but i can't recall anybody needing to use it.
Buzz Fuselsausage: Line Mechanic by night, DC-3 Crew Chief by choice.