See it as a pathological physiological state - a chronic obstructive pulmonary disease. The lung lining can be the Achilles heel in a person. Some people have COPD due to a food intolerance or allergy, like for dust mites or gluten, or pick your choice. It's not necessarily something you inhaled, although that could be very damaging. There is COPD that is more like chronic bronchitis, and there's COPD where's there's emphysema. The first people tend to be overweight, the later are malnourished or have lower weight than average. Some just had a bacterial pneumonia for which they never took antibiotics for, and that left a scar tissue (bronchiectasis) in the lungs. They can have COPD from that. Others have asthma, and that is part of the COPD spectrum of diseases.Nevertheless, key point was what causes COPD?
A person intolerant to gluten will have COPD functional tests that can be reversed or even normalized if they stop gluten and/or stop working at a bakery, provided there's no irreversible damage in the lung lining. At some point, the inflammation is such, that it destroys the lung lining. Then, you can still get better, but here in third density, irreversible damage is still irreversible. Though, the body is incredibly resilient and other parts can learn to pick up the work and compensate well enough with help or therapy.