A person with chronic obstructive pulmonary disease (COPD) has damage to the air passageways in the lungs, usually caused by smoking. The damage causes a persistent cough, wheezing and difficulty breathing. Additional causes include occupational exposure to dust, fumes and smoke.

COPD results in either:

• Chronic bronchitis:
• Damage to the bronchial tubes
• Emphysema:
• Damage to the tiny tubes called bronchioles and the air sacs in the lungs. This leads to air trapping due to the formation of air pockets in the lung tissue.