Patient: Thank you, Dr. Liang. Doctor I would like to inquire if smoking alone can cause the lungs to show such images? That is, is it possible that there is no lesion? Hospital respiratory department: Hello, thank you for the basket of flowers! Smoking generally leads to reduced lung function. However, tobacco contains a component called tar, produced when the cigarette is lit, which contains about 5,000 organic and inorganic chemicals that are not very different in nature from asphalt. People who start smoking under the age of 20, those who smoke more than 20 cigarettes a day, and those who smoke continuously for more than 20 years are 20 times more likely to develop lung cancer than non-smokers. Therefore, it is recommended that your family and friends quit smoking. Also, a word of advice to smokers: It’s never too late to quit!