Monarch Disease Ontology entry MONDO_0004849 (pulmonary emphysema) is a subcategory of chronic obstructive pulmonary disease (COPD). It occurs in people who smoke and suffer from chronic bronchitis. It is characterized by inflation of the alveoli, alveolar wall damage, and reduction in the number of alveoli, resulting in difficulty breathing. Also known as: emphysema, emphysema, pulmonary.