When treating a wound, you CLEAN IT FIRST. That is why a Netti pot works as it cleans any microbes by irrigating the passage so saving the patient from infections.

When treating a respiratory infection, you clean out stinky old yellow and green mucus by percussive therapy, and THEN use medication or herbs to treat the irritation.

It's always the same for any wound. Get all that generally nastiness and debris out, then you can deal with infections.

Your smoker who becomes your patient has chronically irritated lungs AND collected irritants making his dust cells and cilia work five times harder than normal. They are going to be coughing up yellowed plegm for sure and a lung infection is very serious as their poor airway and lungs are RAW.