Exploring Novel Biomarkers for Emphysema Detection

Inclusion Criteria: * Adults aged over 18 years * current respiratory smptoms (any dyspnea, cough or sputum) * spirometry confirmed diagnosis of a non-fully reversible airflow obstruction, defined as a post bronchodilator Forced Expiratory Volume at one second/Forced Vital Capacity (FEV1/FVC ratio) \< 0.7 and/or emphysemateus abnormalities on CT imaging. * presence of risk factors or causes associated with COPD * chest CT scan performed in the past 12 months prior to inclusion to the study * able to understand, read and write Dutch language Exclusion Criteria: * acute exacerbation of COPD within 8 weeks of start of the study * comorbidities affecting speech or breathing coordination (neuromuscular disease, CVA\< BMI \> 40) * comorbidities affecting speech characteristics of dyspnea (severe heart failure, interstitial lung disease) * comorbidities affecting respiratory system including but not exclusive to asthma or cystic fibrosis * comorbidities that significantly interfere with interpretation of speech (audio signals), such as Parkinson's disease, bulbar palsy, or vocal cord paralysis. * Medical history of lobectomy or endoscopic lung volume reduction (ELVR) * inability to carry out a capnography recording. * investigator's uncertainty about the willingness or ability of the patients to comply with the protocol requirements. * participation in another study involving investigational products. Participation in observational studies is allowed.