People realize that smoking has many hazards. Members of WHO 192 unanimously signed a global convention on May 3, 2003, aiming at reducing tobacco use, tobacco harm and death worldwide, and China will benefit greatly from this convention. In China, 63% of men smoke, accounting for 1 3 of the global smokers, making China the largest cigarette market in the world. Smoking does a lot of harm. It not only devours the health and life of smokers, but also pollutes the air and harms others. This should be discussed from six aspects: (1) lung diseases. More than 4000 kinds of chemicals are released when cigarettes are burned, among which the harmful components are tar, carbon monoxide, nicotine and irritating smoke. Tar is harmful to the mouth, throat, trachea and lungs. The villi arranged in the airway of normal lungs usually exclude foreign bodies from lung tissue, and these villi will sweep particles into sputum and mucus and discharge them. Tar in tobacco smoke is deposited on villi, which destroys the function of villi, increases phlegm and causes chronic diseases of bronchus, such as tracheitis, emphysema, pulmonary heart disease and lung cancer. According to statistics, the proportion of smokers suffering from lung disease after 60 years old is 47%, while the proportion of non-smokers suffering from lung disease after 60 years old is only 4%, which is a shocking figure. (2) cardiovascular diseases. Carbon monoxide in cigarettes will reduce the oxygen content in the blood and cause related diseases such as hypertension. Smoking causes coronary artery vasoconstriction, reduces or blocks blood supply, and leads to myocardial infarction. Smoking will increase the secretion of renal gland hormones, cause the heartbeat to accelerate, increase the heart load, affect blood circulation and lead to hypertension, heart disease, stroke and so on. (3) Smoking causes cancer. Smoking can cause cancer. According to statistics, smoking is related to oral cancer, snuff cancer, lung cancer, gastric cancer, intestinal cancer, bladder cancer and breast cancer. Why do you know so little about carcinogenesis? Understanding the carcinogenic mechanism of smoking is of great benefit to help people quit smoking as soon as possible. Tobacco poison is dissolved in water and food, which directly destroys DNA and causes gene mutation. Tobacco contains more radioactive elements, which flow into the body with smoke and damage tissues and cells. If you smoke 30 cigarettes a day, the toxin produced by X-rays can be equivalent to the cumulative dose of 100 X-rays, which will cause gene mutation and cancer. Smoking can also damage people's immune function. Why smokers are prone to catch a cold is because human lymphocytes defend the human body like guards. Smoking will lead to the decrease of lymphocyte activity and lead to cancer. Therefore, in view of the three major causes of cancer caused by smoking, the sooner the better. (4) Smoking will also lead to osteoporosis, and menopause will come early. Smoking can make men lose their sexual function and fertility. Smoking in pregnant women can lead to premature delivery, underweight and increased abortion rate. Smoking makes teeth yellow, which makes bad breath easy. Smoking harms others and yourself. Passive smokers are twice as harmful as smokers. For the health of you and your family, you should quit smoking as soon as possible. (5) The harm of smoking to intelligence. Smoking affects people's attention. Some people think that smoking can refresh their minds, eliminate fatigue and inspire, which is totally unreasonable. Experiments show that smoking seriously affects people's intelligence and memory, thus reducing the efficiency of work and study. Psychologists also used the academic performance of 200 college students as an experimental index, and found that the average score of smokers was 7 points worse than that of non-smokers. Why is this happening? Because nicotine in cigarettes enters the body to stimulate the autonomic nervous system, causing vasospasm, affecting the neural activity of the cerebral cortex, and making people's intelligence decline. (6) Smoking is harmful. In China, 53% of children smoke passively, which is twice as harmful as smokers, and it is more harmful to children, and they are prone to pneumonia, bronchitis, severe asthma and other diseases. If the current smoking situation continues, both children's intellectual development and smokers' families and individuals will pay a huge price.