What is chronic bronchitis?
Chronic bronchitis is a long-term inflammation of the bronchi (breathing passages in the lungs), which results in increased production of mucus, as well as other changes.

These changes may result in breathing problems, frequent infections, cough, and disability.

What is pulmonary emphysema?
Emphysema is a chronic lung condition in which alveoli (air sacs in the lungs) may be:

• Destroyed
• Narrowed
• Collapsed
• Stretched
• Over-inflated

This can cause a decrease in respiratory function and breathlessness. Damage to the air sacs is irreversible and results in permanent "holes" in the lung tissue.

What is asthma?
Asthma is a chronic, inflammatory lung disease involving recurrent breathing problems. The characteristics of asthma include the following:

• The lining of the airways become swollen and inflamed.
• The muscles that surround the airways tighten.
• The production of mucus is increased, leading to mucus plugs.