Study of Microbiological Diversity in Exhaled Air in COPD and Free of COPD

This study is examining what types of microbes (bacteria and other tiny organisms) are present in the air that people breathe out, and whether these differ between people with COPD (chronic obstructive pulmonary disease, a chronic lung condition) and people without it. Researchers hope this could lead to better ways to diagnose and monitor lung disease. **You may be eligible if:** - You have been diagnosed with COPD, OR you are a healthy person without COPD between the ages of 18–30 or 45–70 **You may NOT be eligible if:** - You have taken antibiotics, oral steroids, or immunosuppressant drugs in the past month - You have a chronic lung infection condition (such as bronchiectasis or cystic fibrosis) - You are pregnant or breastfeeding - You are under guardianship or legal protection Talk to your doctor to see if this trial is right for you.