COPDCOPD affects over 24 million people in the United States. COPD is a type of obstructive lung disease characterized by chronically poor airflow. It typically worsens over time. The main symptoms include shortness of breath, cough, and sputum production. The main cause of COPD is tobacco smoking but genetics and environment can also play a role as well. COPD can be monitored by checking monitoring the levels of oxygen in your blood.