Lung cancer is considered by the medical community to be a civilizational disease that continues to manifest itself as society progresses. Since the beginning of the 20th century, the incidence of lung cancer has increased greatly, growing faster than any other cancer. In the 1920s, there were only 370 reported cases of lung cancer in the world, but by the 1950s, the number of people suffering from lung cancer in the United States alone was as high as 18,300, a surprisingly rapid increase. In recent years, the incidence of lung cancer has been increasing even more dramatically. In clinical practice, we often find that people who have never smoked are often found to have lung cancer, a phenomenon that many people often do not understand. Because smoking is a common cause of lung cancer, why do these non-smokers often suffer from lung cancer? This is because of the “second-hand smoke”. American medical researchers recently published a study that some women who live with smokers are six times more likely to develop lung cancer than the average person. The study, which examined the tissues of 106 women living with smokers in Missouri, found that women who had mutations in the gene known as “GSTMI” or who lacked the gene were 2.6 to 6 times more likely to develop lung cancer than the general population. The “GSTMI” gene works by inactivating the carcinogens in tobacco. Because there is no cure for lung cancer, lung cancer prevention is better than cure. We must pay attention to the fact that tobacco harm is one of the most serious public health problems in the world today. There are currently 1.1 billion smokers worldwide, and tobacco kills an estimated 10 million people each year, with one person dying every 10 seconds from the “cigarette” hazard. Smoke emitted by smoking can be divided into mainstream smoke (i.e., smoke inhaled by the smoker) and tributary smoke (i.e., smoke emitted by the ignition of tobacco). Tributary smoke contains more tobacco combustion components than through mainstream smoke. Of these, carbon monoxide is 5 times greater in tributary smoke than in mainstream smoke; tar and nicotine are 3 times greater; ammonia is 46 times greater; and nitrosamines are 50 times greater. According to calculations, in poorly ventilated places, nonsmokers inhaled smoke in 1 hour, the average equivalent of inhaling 1 cigarette dose. Non-smokers who smoke for more than 15 minutes a day are defined as passive smokers, also known as “forced smoking” or “indirect smoking”. The majority of people cannot completely avoid exposure to smoke in their daily lives and therefore become passive smokers. According to the results of a national smoking sample survey, 39.75% of the 343,563 nonsmokers were exposed to passive smoking. The percentage of passive smokers at home was 67.1%, the percentage of passive smokers in the workplace or other public places was 14.4%, and the percentage of passive smokers at home and in public places was 18.96%. The main places of passive smoking are home (71.2%) and public places (32.5%). How to reduce the harm of secondhand smoke is related to the smokers’ own health and the sustainable and healthy development of the social environment. As the Spring Festival approaches, friends and family gather together for a meal and a chat to catch up on friendships. Such scenes can often be seen in major hotels, however, in the hotel, in the box, smokers are often constantly swallowing, non-smokers are often passive inhalation of smoke, even after returning home, on the coat, cashmere sweater and even hair, can smell the smell of smoke, because the smell of smoke permeability is very strong, so it will not be easy to dissipate for a long time, the only way to deal with clothes, bath, or will residue for a long time. The country has long issued a document banning smoking in public places, yet the reality is very different. In order for us all to have a fresh living space, smokers should pay attention to less smoking in public places, especially indoor spaces with poor ventilation, to reduce the pollution of their own and others’ breathing environment. It is best to take the initiative to eliminate or reduce air pollution measures in the home or office, conference rooms and other regular smoking environments, such as placing some green plants such as hanging orchids and ivy, or using air purification equipment. In addition, non-smokers are advised not to stay too long in places where people smoke. At the same time to strengthen awareness of rights and interests, to fully use the rights granted by the regulations, in the office, home and other indoor environments to discourage smokers more, say NO to indoor smokers.