The main causes of lung cancer are the following five points: 1. Smoking causes lung cancer: According to a large number of survey data from various countries, the cause of lung cancer is very closely related to paper cigarette smoking. The increase in the incidence of lung cancer has a parallel relationship with the increase in the sale of paper cigarettes. Paper cigarettes contain many carcinogenic substances such as benzo(a)pyrene. Inhalation of paper cigarette smoke or application of tar in experimental animals can induce respiratory and skin cancer. The incidence of lung cancer is 10 times higher in people with smoking habits than in nonsmokers, and the incidence is even higher in heavy smokers, 20 times higher than in nonsmokers. 2. Chronic lung diseases can cause lung cancer: some people are not aware of chronic lung diseases, which may be the cause of lung cancer, such as pneumoconiosis, silicosis and tuberculosis. Once suffering from these lung diseases, the chances of developing lung cancer are high. If you want to carry out lung cancer prevention, you should be alert to these diseases as well. Moreover, if you suffer from lung fiber scar lesion or non-bronchial chronic inflammation, it will also slowly turn into lung cancer, which is also one of the causes of lung cancer. 3.Lung cancer can be caused by family environment: the decoration materials of the house and the fumes from cooking contain many ulcer-causing substances, and passive smoking caused by smoking among family members can also pollute the small family environment. The cause of lung cancer in women may be related to the long-term inhalation of cooking fumes. 4.Occupational disease factors can cause lung cancer: This is because some jobs require daily exposure to radioactive substances such as radium, uranium and mustard gas, asbestos, petroleum, asphalt, coal tar, arsenic, chromium, nickel, copper, tin and other carcinogenic substances, which are all causes of lung cancer, and those who work in this area should pay more attention to lung cancer prevention. 5.Atmospheric pollution can cause lung cancer: prevention of lung cancer requires improvement of atmospheric pollution. The incidence of lung cancer in many industrially developed countries is extremely high, and the incidence is higher in urban than rural areas, and higher in factories and mines than in residential areas. The main cause of lung cancer in this area is due to the pollution of the atmosphere by harmful substances such as benzo(a)pyrene carcinogenic hydrocarbons produced by burning oil, coal and internal combustion engines and asphalt road dust in industrial and transportation developed areas.