Lung cancer is a “cunning” disease, which basically has no special symptoms in the early stage. Such diseases as irritating dry cough, coughing up blood, chest pain, fever, pestle and mortar, arthritis, etc., which seem to be unrelated to lung cancer, may be lung cancer “reporting” to you and should be paid extra attention. Smoking is the most important cause of lung cancer. The majority of lung cancer cases can be attributed to tobacco exposure, with smokers having 24 times the risk of developing lung cancer compared to nonsmokers. Therefore, effective tobacco control interventions can significantly curb the rise in lung cancer incidence and mortality, and smokers will have a reduced risk of developing lung cancer even if they quit in midlife. It’s never too late for smokers to quit, but the sooner the better! So, whether for yourself or for others, you should quit smoking in a hurry! Tobacco combustion can produce more than 4,000 chemicals, like polycyclic hydrocarbons (such as benzo(a)pyrene), nitrosamines and aromatic amines, among which as many as 60 types of carcinogens have been identified. In addition, the harm of secondhand smoke should not be underestimated. According to data, the risk of lung cancer is much higher for non-smokers who are in a long-term smoking environment than for non-smokers in a normal environment. Non-smoking women married to smoking men have a significantly higher risk of dying from lung cancer than women married to non-smoking men. In addition to smoking, air pollution, frying fumes, automobile exhaust, and industrial emissions are important causes of lung cancer. Asbestos, inorganic compounds of arsenic, chromium, nickel, and cadmium compounds, coal tar asphalt volatiles, computer radiation, and sulfuric acid fumes are also causative factors of lung cancer.