What does it mean for your lung to collapse and how to avoid it?

A collapsed lung is when air gets between the lung and the chest wall and when this happens the lung cannot will up with air to take a breath. You can prevent having a collapsed lung by not smoking, that is the key way for prevention of an collapsed lung.

http://www.emedicinehealth.com/collapsed_lung/article_em.htm

http://www.emedicinehealth.com/collapsed_lung/page9_em.htm#collapsed_lung_prevention