The physiological effects of smoking on the respiratory system.

Knowledge about the harmful effects of smoking on the lungs is high among the general population. This damage can occur to both active and passive smokers. Although scientific understanding in this area is incomplete we do have some knowledge about how individual toxic substances in cigarette smoke act on the lung tissues. There is great variation in smokers' susceptibility to the harmful effects of tobacco dependence. The reasons for this are complex and the role of genetic factors requires more research.