It’s been observed that even former smokers who quit years ago have traces of lung damage. Even if one has never smoked, second hand cigarette smoke, industrial pollution, vehicular exhaust fumes and now chemtrails with downward drifting heavy metal nano-particles all contribute to some level of lung damage for almost everyone.
So whether you once smoked or never puffed on chemical-laden, radioactive (from the fertilizer) tobacco, detoxing and regenerating lung tissue may still be appropriate for you.
By the way, the notion that lung damage is irreparable is not true. With proper nourishment and nurturing, your lungs can repair damaged tissues eventually.