Secondhand smoke, also known as passive smoking, refers to the behavior of non-smokers absorbing the smoke emitted by other smokers. Generally speaking, when the duration of passive smoking exceeds 15 minutes, it can be considered that the phenomenon of second-hand smoke is established.
Secondhand smoke is actually composed of two kinds of cigarettes, one is the smoke exhaled by smokers, which is called mainstream smoke; One is the smoke produced when cigarettes burn, which is called split smoke. No matter what kind of smoke a non-smoker inhales, it is second-hand smoke.
Experts have found that some smokers have great misunderstandings. They think that second-hand smoke should be defined as the smoke that comes out when the cigarette burns itself (that is, the shunt smoke), and the smoke that comes out after being filtered by the smoker's lungs (that is, the mainstream smoke) is definitely not so toxic, so second-hand smoke is definitely not as harmful as one-handed smoking. In fact, their mistake is that they don't understand the definition, composition and harm of secondhand smoke. After reading the following, they will know a lot.
As we all know, in daily life, due to the differences in culture, living habits and environmental awareness, most people can't completely avoid exposure to cigarette smoke, so the phenomenon of second-hand smoke is very common.
Second, how does second-hand smoke harm the human body
According to research, there are more than 4000 kinds of harmful substances in the smoke after cigarette combustion, which can be divided into four categories from the medical point of view:
1. The concentration of carbon monoxide in cigarette smoke is about four ten thousandths, and its binding force with red blood cells is about 265,438+00 times that of oxygen and red blood cells. Therefore, after carbon monoxide is inhaled into the human body, the ability of red blood cells to transport oxygen will be reduced, leading to hypoxia in the body.
2. Nicotine, after entering the human body, will have the following effects: peripheral blood vessels of limbs contract, the heart beats faster, blood pressure rises, breathing becomes faster, mental state changes (becomes emotional stability or mental excitement), and promotes platelet aggregation, which is the main accomplice of cardiovascular diseases such as cardiovascular obstruction, hypertension and stroke.
Third, irritating substances, these substances will not only stimulate the eyes, nose and throat, but also stimulate the secretion of bronchial submucosal glands, leading to acute bronchitis and chronic bronchitis.
4. Carcinogen: In addition to the recognized carcinogen nicotine, smoke also contains more radioactive elements, such as polonium, which volatilizes when smoking, is absorbed by the human body and accumulates in the body, constantly releasing alpha rays, thus damaging the tissues and cells of the body, damaging the immunity of the human body and creating an environment for the growth of cancer cells.
There is no doubt that the above four kinds of harmful substances have the same harm to smokers and second-hand smoke. What is more noteworthy is that the content of some harmful substances in the shunt flue gas is higher than that in the mainstream flue gas, such as carbon monoxide, which is five times that of the mainstream flue gas; Tar and nicotine are three times; Ammonia is 46 times; Nitrosamine (a strong carcinogen) is 50 times. The results also show that the influence of second-hand smoke on the body is similar to that of smokers, because the urine test of second-hand smoke smokers found that their urine also contains metabolites such as nicotine.
The research team led by Stayner, an epidemiologist at the University of Illinois in the United States, said in the American Journal of Public Health in 2007 that after analyzing 22 survey data of secondhand smoke pollution collected from the United States, Canada, Europe, India, Japan and China, it was found that non-smokers working in places heavily polluted by secondhand smoke had the same risk of lung cancer as active smokers.
Third, how harmful is the frequent use of secondhand smoke?
Leading to lung cancer and coronary heart disease
Surveys in Japan, Sweden, Britain, the United States, Hong Kong and other countries and regions show that the risk of lung cancer is 1.5-2 times that of a non-smoking wife living with a non-smoking husband for a long time. The more husbands smoke, the longer they live together, and the more miserable their wives are. The reason why passive smoking leads to coronary heart disease is that the chemicals inhaled by passive smoking can make blood lipid abnormal, blood sticky, destroy myocardial tissue, reduce the ability of blood vessels to regulate blood pressure and blood flow, and then increase the risk of myocardial infarction.
Causing leukemia and tumors
A study in the United States shows that smoking by a husband will increase the risk of leukemia by seven times for a non-smoking wife. The risk of breast cancer and cervical cancer in women aged 6-45 who smoke passively at home is 3-4 times that of women in non-smoking families.
Leading to infertility, birth defects, stillbirth and abortion.
Female health experts' research on infertility shows that nicotine can reduce the secretion of sex hormones and kill sperm. Smoking 30 cigarettes a day, the sperm survival rate is only 49%, and the mortality rate is 5 1%. A husband's smoking can reduce the possibility of his wife's pregnancy by half.
Birth defects Smoking can damage sperm and pass this damage on to children. After investigating 0/5,000 children in the United States/KLOC-0, it is found that parents smoke more than 20 cigarettes a day, and their children are at risk of congenital defects such as cleft lip, valvular heart disease or urethral stricture, which is nearly 50% more than those born to parents who don't smoke, and most of them are caused by their fathers' smoking. Passive smoking in pregnant women can also reduce the zinc content in fetal blood and affect fetal brain development.
Stillbirth and abortion. Danish scientists found through a survey of 500 women that smoking in pregnant women will increase fetal mortality. If the husband smokes more than 10 cigarettes a day, the fetal mortality rate will increase by 60%. The more you smoke, the higher the death rate. Every year in Britain, 7,500 pregnant women have miscarriages or premature births, and about 450 newborns die within a short time after birth. Scientists have come to a similar conclusion through investigation.
Studies have shown that in the early pregnancy, due to the action of nicotine and its metabolites, the secretion of progesterone in pregnant women is reduced, which affects the decidual reaction of endometrium, makes it difficult for pregnant eggs to implant, and leads to termination of pregnancy or spontaneous abortion. The more pregnant women smoke passively, the greater the risk of miscarriage or premature delivery. Fetal intrauterine asphyxia or death occurs because nicotine can reduce the oxygen content in placenta. In order to meet the needs of the fetus, the placenta is compensatory to increase, and too large placenta is prone to basal necrosis and trophoblast hyperplasia, and umbilical artery malformation may also occur. These pathological changes can lead to fetal asphyxia or death.
In short, second-hand smoke is harmful to women's health, so it is suggested that smokers should think about their female friends and their health before smoking, and it is best to give up smoking completely and devote themselves to work and life better.
From a macro perspective, legislation is the ultimate means to effectively prevent the harm of second-hand smoke. But from the perspective of the whole world, all countries have made progress in this regard.
However, preventing a smoker from smoking is a big problem. But as a family, we can secretly give him smoking cessation drugs or give him toothpaste to quit smoking. He always has to brush his teeth. After brushing his teeth, he will feel bitter and uncomfortable somehow. Hehe, so he won't smoke. Of course, ideological education is the most important thing, so that the elderly can fully realize the harm of smoking to health.