Are you a “passive smoker”? Secondhand smoke should never be interpreted as taking over someone else’s unused cigarettes and smoking them again, like buying a used car. By secondhand smoke, we mean that nonsmokers inhale the environmental cigarette smoke caused by smokers. Passive smoking (secondhand smoke) is one of the most controversial risk factors for lung cancer. Passive smoking is commonly referred to as “secondhand smoke”. Foreign studies have shown that exposure to heavy passive smoking is equal to that of smoking a few cigarettes a day. Secondhand smoke is no less harmful to passive smokers than to active smokers, and is especially harmful to children and adolescents. Surveys show that the main victims of passive smoking in China are women and children, who are often exposed to secondhand smoke from others in homes and public places, even though they do not smoke themselves. In addition, workplaces, meeting places, etc., are often places where secondhand smoke is prevalent. Although they do not smoke cigarettes directly, but exhale into the body, but still can cause harm to the body, even more than smokers. Non-smokers and smokers living or working together, smelling smoke for a quarter of an hour a day for more than a year can be as harmful as smoking. Some women who live with smokers are six times more likely to develop lung cancer than the average person. May 31, 2014 was the 27th World No Tobacco Day, but a smoke-free day still seems out of reach. on May 29, 2007, China’s Ministry of Health released the 2007 China Smoking Control Report. According to the report, 540 million people in China suffer from passive smoking, including 180 million children under the age of 15, and more than 100,000 people die from passive smoking each year, while the awareness rate of the dangers of passive smoking is only 35 percent. According to data released in August 2010, the number of people suffering from secondhand smoke in China has reached 740 million. If secondhand smoke is not prevented early, it will bring a heavier medical burden. While smoking harms the health of smokers themselves, secondhand smoke also affects non-smokers. In addition to irritating the eyes, nose, and throat, it also significantly increases the chance of lung cancer and heart disease, as well as other respiratory diseases that can seriously harm people’s health. The harmful substances inhaled by passive smoking are often more powerful than those inhaled by active smoking. This is because the smoke emitted by smoking can be divided into mainstream smoke and sidestream smoke. Mainstream smoke is the smoke that the smoker inhales into the mouth; sidestream smoke is the smoke that comes out of the tobacco after it is lit. The mixture of smoke exhaled by the smoker and the smoke emitted when the cigarette is lit is called secondhand smoke, also known as passive smoking. Secondhand smoke often contains more harmful substances than mainstream smoke, for example: two times the nicotine, three times the tar, five times the carbon monoxide and about 50 times the carcinogenic substances. According to calculations, in poorly ventilated places, non-smokers inhale the amount of smoke in an hour, the average equivalent of inhaling a cigarette dose. In addition, smokers have their own fixed time period for smoking, while passive smokers smoke multiple times, continuously and repeatedly to the smoke exhaled by multiple smokers. When someone smokes in a poorly ventilated room, the most common symptoms for nonsmokers are irritation of the eyes, headache, and cough. People who inhale secondhand smoke will experience the same symptoms as smokers. Therefore, it is said that secondhand smoke is more harmful.