1.What are the risk factors leading to lung cancer? (1) Smoking: It is well known that smoking is the most important risk factor for lung cancer, and more than 40 carcinogenic substances can be produced in the process of smoking. Studies have found that men who smoke more than 2 boxes a day have 20.4 times the risk of lung cancer than normal people. The greater the amount of smoking and the longer the smoking time, the greater the risk. (2) Air pollution: the level of pollutants in the air is directly proportional to the probability of developing lung cancer. for every 10 micrograms increase in pollutants in 1 cubic meter of air, the probability of developing lung cancer increases by 8 percent. The increased incidence of lung cancer in women is now thought to be more closely related to kitchen fumes. People who are exposed to dust or asbestos at work also have an increased risk of lung cancer. (3) History of previous lung diseases: such as asthma, chronic obstructive pulmonary disease, pneumonia and tuberculosis are risk factors for lung cancer, with tuberculosis being the most closely related. (4) Dietary imbalance: High-fat and high-cholesterol diets and alcohol consumption can increase the risk of lung cancer. (5) Psychological factors: poor psychological adaptability and long-term mental depression will increase the risk of lung cancer. 2.What are the preventive measures for lung cancer? (1) Quit smoking and refuse passive smoking: 80-90% of lung cancers are caused by active smoking or passive second-hand smoking, so it is very important to promote smoking cessation or ban smoking in public places to prevent lung cancer. Some people believe that some long-term smokers also live to be over 90 years old and use this as a reason not to quit. Since we all have different genes and different lifestyles, a few of us may be resistant to the carcinogens produced by smoking and may not cause the activation of cancer genes, etc., but we should not take any chances because of this. Others argue that for long-term smokers, suddenly quitting is more likely to cause cancer. A study from the UK gives a clear answer to such an argument. The study conducted a comprehensive analysis of smoking, smoking cessation and lung cancer prevalence trends in the United Kingdom since 1950, and found that smokers who quit even in middle age reduced their risk of developing lung cancer later in life, and that quitting before middle age reduced the risk of tobacco-induced lung cancer by more than 90 percent. Since the 1960s, countries such as the United Kingdom and the United States have been vigorously promoting the health hazards of smoking, resulting in an annual decrease in the smoking rate of the population by 1 to 2%. Therefore, quitting smoking and refusing passive smoking are currently the most effective ways to prevent lung cancer. (2) Control of air pollution: Regarding the control of air pollution and occupational diseases, the supervision and management of government departments are needed. For us as individuals, it is very important to develop the habit of wearing a mask when we go out. In addition, in order to prevent indoor pollution, we have to keep the kitchen ventilation, kitchen must be installed hood or exhaust fan; cooking is best not to let the frying pan smoke, less frying cooking method; interior decoration to use environmentally friendly materials, try to ventilate for a period of time after the completion of the decoration before moving in. (3) Dietary prevention: The intake of more vegetables and appropriate amount of fresh fruits has a protective effect on lung cancer. The larger the intake, the more obvious the protective effect. Because vegetables and fruits mainly contain vitamins and trace elements, which have the functions of inhibiting DNA amplification of cancer cells and blocking synthesis of carcinogenic substances, respectively. Some scholars found that cruciferous vegetables (such as rape, cauliflower, cabbage, Chinese cabbage, kale, cauliflower, turnip greens, etc.) have more prominent protective effects on lung cancer. Increasing the intake of vegetables and fruits, especially foods rich in carotenoids, vitamin C, vitamin E, folic acid and trace elements of selenium, can reduce the incidence of lung cancer. (4) Others: Maintain good living habits, such as living a regular life, having a happy mood, combining work and rest, and actively exercising to increase the ability to prevent and fight diseases. You should check your body regularly, and when symptoms such as irritating dry cough and blood in sputum appear, you should go to hospital for examination in time.