Chronic Obstructive Pulmonary Disease (COPD) Co-Pilot AIR Substudy of CLN0014

Inclusion Criteria: 1. Participant has read, understood, and signed a CLN0020 informed consent form prior to enrollment. 2. Participant is appropriate for Coil treatment per the Conformité Européene (European Conformity \[CE\])-Mark Approved RePneu Instructions for Use (IFU). 3. Participant has been enrolled in and scheduled for treatment(s) with the PneumRx Endobronchial Coil procedure in the CLN0014 study. 4. Participant's PneumRx Endobronchial Coil procedure is scheduled to occur no fewer than 14 days from enrollment, providing enough time to establish a baseline of their daily symptoms. Ten days minimum of baseline data are required, which is defined as the Run-in period going forward. 5. Participant is willing and able to use a smart phone. Exclusion Criteria: 1. Participant has undergone a Coil procedure. 2. Participant has had an acute exacerbation of COPD that required hospitalization or emergency room visit or treatment with systemic steroids and/or antibiotics during the 28 days prior to CLN0020 enrollment. 3. Participant has a COPD exacerbation or respiratory illness during the Run-in period that in the judgment of the investigator requires medical intervention (for example, treatment with systemic steroids and/or antibiotics and/or hospitalization). 4. Participant is suffering from terminal illness expected to adversely affect survival in the next 12 months. 5. Participant has a history of non-compliance with medical therapies.