They focus on the respiratory system, which includes the lungs, airways (bronchi, trachea), and chest structures. 

Pulmonologists treat a wide range of respiratory conditions, such as asthma, COPD, pneumonia, tuberculosis, lung cancer, and sleep apnea. 

They diagnose, treat, and manage lung and respiratory problems. This may involve performing lung function tests, prescribing medications, or ordering additional tests or procedures like bronchoscopy or sleep studies. 

You might be referred to a pulmonologist by your primary care physician or if you experience symptoms like persistent cough, shortness of breath, or chest pain.