Chronic obstructive pulmonary disease (COPD) is the name for a group of lung conditions that cause breathing difficulties which include emphysema (damage to the air sacs in the lungs) and chronic bronchitis (long-term inflammation of the airways).
COPD is a common condition that mainly affects middle-aged or older adults who smoke. Many people don't realise they have it. The breathing problems tend to get gradually worse over time.
You can read more about COPD on the NHS website.