Although nicotine is the addictive substance in tobacco, it is not nicotine that does most of the damage to a smoker's health. Tobacco smoke contains more than 4,000 chemicals, according to the Centers for Disease Control and Prevention, and the act of inhaling these chemicals into the lungs puts the smoker at risk for a variety of ailments, some of which are deadly.
Mechanism
When tobacco is ignited, it produces tar, which enters your lungs through tobacco smoke. Your immune system sends cells to protect your lungs from this invasion, but these cells are quickly overcome by tobacco smoke and die, according to the British Lung Foundation. These dead immune cells release chemicals that cause further damage to your lungs.
COPD
COPD stands for chronic obstructive pulmonary disease and actually refers to two harmful conditions caused by smoking: chronic bronchitis and emphysema. The National Heart Lung and Blood Institute reports that tobacco smoking is the primary cause of COPD. Tobacco smoke causes COPD by damaging or destroying the lungs' airways and air sacs. Emphysema results when smoke causes the lungs' air sacs to lose elasticity and destroys the walls separating individual sacs. Chronic bronchitis results when smoke inflames the lungs' airways, causing mucus to form that obstructs breathing. Once you have COPD, you cannot make a full recovery even if you quit smoking.
Lung Cancer
Lung cancer is one of the deadliest forms of cancer: Its five-year survival rate is only 15.6 percent, according to the American Lung Association. Smoking is responsible for the vast majority of lung cancer cases, especially those in women. Lung cancer kills at least 150,000 people a year in the United States and many more worldwide.
Secondhand Smoking
Secondhand smoking occurs when you breathe tobacco smoke exhaled by a smoker or emitted from burning tobacco. Although it is not as dangerous as direct smoking, secondhand smoking represents a definite and sometimes fatal health hazard, especially if you live or work with a smoker and are thereby constantly exposed. The American Lung Association estimates that secondhand smoking is responsible for more than 3,000 lung cancer deaths a year in the United States.
Quitting
If you have smoked for many years, quitting will not reduce your risk level to that of someone who has never smoked. Nevertheless, you can reduce your risk to considerably less than it would have been if you had continued smoking, and the sooner you quit, the greater the benefits will be. The American Cancer Society reports that quitting can greatly improve the functioning of your lungs within a single month, and can reduce the risk of cancer and disease thereafter.
