Women who cook in a smoke-filled room have a 60% higher risk of lung cancer than women in a room with no or little smoke, and the more often and the longer the exposure to fumes, the greater the risk of lung cancer. Cooking with coal for more than 15 years can increase the risk of lung cancer by 125%, while cooking with gas can reduce the risk of lung cancer by 70%. Hunan conducted a 25-year epidemiological survey on the cause of death of 2345 cooks (1099 men and 1139 women). The crude mortality rate of lung cancer was found to be 98.2 per 100,000. Xuanwei in Yunnan reached 33.3/100,000 in 1970s, which was related to indoor coal-fired heating and cooking food. In addition, radon, chromium, iron and uranium; previous lung diseases (tuberculosis, chronic bronchitis) are also related to the development of lung cancer. 1.Cough: incidence 46%, which can be manifested as irritating dry cough, continuous and metallic sound of cough (mostly central lung cancer). 2.Hemoptysis: incidence 27%, which can be blood in sputum, blood clots, or hemoptysis (life-threatening in serious cases). 3. Chest pain: 30% incidence, which is vague pain and discomfort. 4.Shortness of breath: 30% incidence, when the lung mass is large or there is pleural effusion, then shortness of breath appears. 5, fever: incidence 28%, generally low fever, high fever may appear when combined with lung infection.