The concept of “third-hand smoke” was first proposed by U.S. experts, referring to the fact that hours or even days after the smoke is extinguished, a mixture of toxic substances emitted during the smoking process will remain on the surface of the home, carpets, walls, clothes and other objects indoors, containing toxic components including hydrocyanic acid, butane, toluene, arsenic, lead, carbon monoxide, radioactive elements polonium 210 and more than a dozen other highly carcinogenic compounds, Carbon monoxide, the radioactive element polonium 210 and more than a dozen other highly carcinogenic compounds. Compared to “secondhand smoke”, “thirdhand smoke” is more insidious. Frequent inhalation of “third-hand smoke” may be one of the reasons why some people who have never smoked develop lung cancer. Children are more susceptible to the dangers of third-hand smoke: Because children have a lower body weight than adults, the same levels of toxic substances are more harmful to children. When children crawl or play on floors and carpets, they are easily exposed to these harmful substances; the most direct consequence of skin absorption of these harmful substances is that they cause respiratory problems in infants and children, such as acute bronchitis and asthma. Simply isolating children from the smoke produced when smoking does not really protect them. Even when smoking outside, nicotine levels in infants in smokers’ homes are still seven times higher than in infants in non-smoking homes. If you have infants and young children in your home who cannot quit smoking, it is best not to smoke at home and to change your clothes, rinse your mouth and wash your hair when you get home to reduce the harmful effects of “third-hand smoke”.