Chronic Obstructive Pulmonary Disease (COPD) is a collective term that refers to several lung diseases. It causes damage to your lungs over time, blocks airflow, and creates breathing difficulties. Chronic bronchitis and emphysema are the two most common medical conditions associated with COPD. More than 24 million people suffer from COPD in the United States, of which only 13 million are reported cases, according to the American Lung Association.
