COPD is a term used to describe a group of progressive lung diseases, including emphysema and chronic bronchitis, that obstruct airflow and make breathing difficult. These conditions typically develop over time due to long-term exposure to lung irritants, such as cigarette smoke, air pollution, or occupational hazards. Diagnosis of COPD usually involves the use of lung function tests, such as spirometry, considered in line with the patients symptoms and medical history.