The purpose of this study is to investigate how mucus (phlegm or spit) is broken down once it forms in the airways (bronchial tubes) of people with lung disease. This research study will also examine whether blood groups have an effect on lung function or the type of mucus found in the lung. This study is not designed to be a treatment for asthma, emphysema, cystic fibrosis, or other lung disease. It is designed to help the investigators learn more about the causes of airway disease.