1. Emphysema is a serious respiratory disease caused by smoking, people who suffer from emphysema have trouble exhaling air from their lung. Alveoli are damaged of a person who suffers from emphysema. It evolve slowly over the year. Over time inner walls alveoli (air sac) become weaken and get rupture. Thus creating larger air spaces instead of small ones resulting reduced surface area of the lungs, in turn, the amount of oxygen reaches to bloodstream become less.