Clinical Feasibility of a Non-invasive Wearable Acoustic Device for Measuring Air Trapping in COPD

This is a pilot observational study during which the investigators will conduct a longitudinal assessment of air trapping (with up to 2 visits) in 40 patients with COPD and variable degrees of air trapping and 20 healthy controls using ARIA. The investigators will characterize the clinical phenotype of the subjects by administering health and symptom-based questionnaires and obtaining lung function testing at rest and during exertion, and will then correlate and validate the ARIA-based indices with those of the more traditional physiologic measures of static and dynamic air trapping.