According to the American Lung Association, Chronic Obstructive Pulmonary Disease (COPD) is the third leading cause of death in the United States, with about 12.7 million adults over the age of 18 suffering from the disease in 2011. Additionally, an estimated 10.1 million Americans were reported to have chronic bronchitis, which exacerbates COPD. Risk factors for COPD include smoking, heredity, occupational exposure to dust or chemicals and air pollution.