According to a new study, smoking can shorten people's life span 1 1 minute. If you smoke a pack of 20 cigarettes a day, it may reduce a person's life span by about 3 hours and 40 minutes. This estimate is based on people who started smoking at the age of 17 and died at an average age of 7 1 7. Suppose he smokes 15 cigarettes a day like the average British addict, he will consume 3 1 1688 cigarettes in his life. On average, smokers die six and a half years earlier than non-smokers. A similar study decades ago concluded that every cigarette smoked would shorten life expectancy by five minutes. But since then, non-smokers have obviously enjoyed a longer life span, so the harm of cigarettes to life span has increased relatively. At present, about one-third of people in Britain smoke, and about120,000 people die of smoking-related diseases every year, two-thirds of which are cancer and heart disease. Researchers hope that this new study will encourage more people to make up their minds to quit smoking at the dawn of the new century. The host of a smoking cessation action group said that this figure shows that if a person smokes 20 cigarettes a day, it means that he will lose one day every week he smokes; If this is not bad enough, he warned that smoking may also make people die painfully, or they may get sick more often. Tobacco smoke contains at least three dangerous chemicals: tar, nicotine and carbon monoxide. Tar is a mixture of several substances, which will be concentrated into a viscous substance in the lungs. Nicotine is an addictive drug, which is absorbed by the lungs and mainly acts on the nervous system. Carbon monoxide reduce that ability of red blood cells to deliver oxygen to the whole body. A person who smokes/kloc-0.5 to 20 cigarettes a day is four times more likely to develop lung cancer, oral cancer or laryngeal cancer and die than a non-smoker. The mortality rate of esophageal cancer is four times higher than that of non-smokers. The risk of dying from bladder cancer is twice as high; The risk of dying of heart disease is twice as high. Smoking is the main cause of chronic bronchitis and emphysema, and chronic lung disease itself will increase the risk of pneumonia and heart disease, and smoking will also increase the risk of hypertension.