Radioactive damage: Tobacco absorbs radioactive substances from soil, fertilizer and air more easily than other plants during its growth, resulting in more radionuclides in tobacco. Among them, a radioactive substance called polonium is the most harmful. This substance volatilizes when people smoke, accumulates in the body with the smoke flowing into the human body, and continuously releases alpha rays invisible to our naked eyes, damaging the tissues and cells of the body. It is estimated that if you smoke 30 cigarettes a day, the annual dose of alpha-ray exposure to human body is equivalent to the cumulative dose of 100 x-rays. This kind of irradiation will affect the metabolism of tissues and cells, make cell genes mutate, and induce and promote the formation and development of cancer.
Impairment of immune function: Smoking can impair human immune function, which is positively related to the infection of smokers and the increase of tumor incidence. The reason why the human immune system can exert its immune function is that there is a natural killer cell-NK lymphocyte in the system, which can directly inhibit and kill cancer cells. Smoking will lead to the decline of NK cell activity, and the more smoking, the lower its activity. Relevant data show that the NK cell activity of heavy smokers who smoke more than 150 packs a year is significantly lower than that of non-smokers.
Destruction of cell genes: Tobacco contains many carcinogens, such as nicotine, pyridine, hydrochloric acid, ammonia, tobacco tar, carbon monoxide and aromatic compounds, among which tobacco tar is the most harmful. Tobacco tar contains radioactive isotopes of magnesium, lead and bismuth as well as epoxides, phenols, benzene and pyrene. These carcinogens are everywhere, and the best trick is to drill into gene bases and destroy the structure of DNA. If the damaged DNA is not repaired in time, the diseased gene will be transferred to the offspring cells and become potential cancer cells. When affected by other factors, cancer cells will proliferate and form cancer. The "reactive oxygen species" produced by lipid peroxide dissolved in water or food can directly act on deoxyribonucleic acid, breaking its chain into fragments, especially destroying the deoxyribonucleic acid of cells with oncogenes, thus promoting gene mutation, causing cell canceration and forming cancer.
Because the toxic substances inhaled by passive smokers are several times to 50 times more than those inhaled by active smokers, they can invade the lungs and damage the inner wall cells of arteries, thus promoting atherosclerosis. In addition to lung cancer, it can also cause brain cancer, thyroid cancer, breast cancer and cervical cancer. A follow-up observation on the incidence of lung cancer in 9 1540 non-smoking housewives over 40 years old showed that the relative risk rate of lung cancer in the wives of non-smokers was 1, that of moderate smokers was 1.6 1, and that of heavy smokers was 2.08. It was also found that the annual standard mortality rate of female lung cancer who did not smoke or smoked passively was 8.7/65438+ 10,000. The annual standard mortality rate of passive smoking female lung cancer is 15.5/65438+ 10,000. After a lot of research, the conclusion is: if the same smoker lives together, the risk of cancer will increase by 1.4 times; Living with two smokers increases the risk of cancer by 2.3 times; Living with more than three smokers increases the risk of cancer by 2.6 times. The probability of suffering from leukemia is also 6.8 times that of the average person.