Name the chronic respiratory disorder caused mainly by cigarette smoking. Emphysema, Asthma, Respiratory acidosis, Cough

Emphysema is a destructive disease of the lung in which the alveoli (small sacs) that promote oxygen exchange between the air and the bloodstream are destroyed. Smoking is the primary cause of emphysema, which makes it a preventable illness. Most commonly, the toxins in cigarette smoke create the damage. The primary symptom of emphysema is shortness of breath. It is a progressive complaint by affected individuals, worsening over time. Early in the disease, shortness of breath may occur with exercise and activity but symptoms gradually worsen and may occur at rest.