In 1831, the Englishman Faraday discovered the phenomenon of electromagnetic induction. On the basis of this discovery, the Scotsman Maxwell predicted the existence of electromagnetic waves. Subsequent research found that there is an electromagnetic field around alternating current, and that the energy of the electromagnetic field propagates to the surrounding space in the form of "electromagnetic waves", a process known as "electromagnetic radiation".
There are many sources of electromagnetic radiation, generally speaking, there are natural electromagnetic radiation and artificial electromagnetic radiation.
Natural electromagnetic radiation is spontaneously generated by nature, such as lightning, sunspot activity, earthquakes and volcanic eruptions can produce electromagnetic radiation. Natural electromagnetic radiation has existed since the creation of the Earth, mankind in the long process of evolution has adapted to the natural electromagnetic radiation produced by nature, usually natural electromagnetic radiation are within a certain safety threshold, human beings have a certain degree of adaptability.
Artificial electromagnetic radiation is mainly produced by human production activities in the process of electromagnetic radiation. After entering the era of electrification, out of the needs of production and life, a large number of electrical appliances were manufactured, the environment of electromagnetic radiation mainly into artificial radiation. In today's society, radar systems, television and radio transmission systems, radio frequency induction and medium heating equipment, radio frequency and microwave medical equipment, all kinds of electroprocessing equipment, communication transmitter stations, satellite earth communication stations, large-scale electric power stations, power transmission and transformation equipment, office automation equipment, high-voltage power lines, subway trains, electric trains, and microwave ovens, radios, televisions, cell phones, computers and WIFI routers, etc. can generate different forms of different forms of electromagnetic radiation. etc. can produce different forms, different frequencies, different intensity of electromagnetic radiation.
Electromagnetic radiation is different from other forms of energy transformation, it is an invisible, intangible magnetic field. Since electromagnetic radiation is a kind of energy propagation, then its energy should be big and small. According to the quantum point of view, electromagnetic radiation is composed of photoelectrons, and its energy depends on the frequency. Generally speaking, the larger the frequency, the smaller the wavelength, the greater the intensity of electromagnetic radiation; the smaller the frequency, the larger the wavelength, the smaller the electromagnetic intensity.
Electromagnetic waves are categorized by frequency: long wave, medium wave, short wave, ultra-short wave and microwave. Generally speaking, the impact of long waves on the human body is weak, the shorter the wavelength, the higher the frequency, the greater the impact on the human body, the most prominent impact of microwaves.
When the intensity of electromagnetic radiation exceeds the limits that the human body or the environment can withstand, it will cause electromagnetic radiation pollution.
Electromagnetic radiation pollution refers to the intensity of electromagnetic radiation exceeds the background value, exceeding the maximum permissible limit of organisms or electrical equipment, the health of living organisms caused by the impact of the normal operation of electrical equipment.
Electromagnetic radiation pollution is related to the characteristics, power, density and frequency of electromagnetic waves.
Natural electromagnetic radiation pollution impact is small, because it is the natural choice to finally achieve a harmonious **** biological relationship, while artificial electromagnetic radiation caused by pollution on the environment. People often say that electromagnetic radiation pollution mainly refers to the artificial type of electromagnetic radiation, artificial type of electromagnetic radiation pollution will cause physical discomfort in the organism, will have an impact on the normal use of electrical equipment, is to be particularly precautionary type of electromagnetic radiation.
Over the past few decades, domestic and foreign media reports on the harmful effects of electromagnetic radiation have been uninterrupted,
Sweden and other three Nordic countries, a study showed that long-term exposure to electromagnetic radiation more than 2mG, the chances of suffering from leukemia is 2.1 times the normal people, the chances of suffering from brain tumors is 1.5 times the normal people, the incidence of other diseases also increased significantly.
A survey report by the World Health Organization shows that electromagnetic radiation is one of the main causes of cardiovascular disease, diabetes, and cancer, and can cause direct harm to the human reproductive system, nervous system, and immune system, which can lead to a decline in male sexual function, female endocrine disorders, menstrual disorders. Prolonged exposure to high electromagnetic radiation will change the blood, lymph fluid and cell protoplasm, affecting the circulatory system, immunity, hormone secretion, reproduction and metabolism, and in serious cases will induce cancer, diabetes, hereditary diseases and other conditions. Patients with pacemakers are exposed to high electromagnetic radiation, which can affect the normal use of pacemakers. More seriously, high-intensity electromagnetic radiation also has a considerable adverse effect on the fetus.
Electromagnetic radiation mainly through the thermal effect, non-thermal effect and cumulative effect on the organism:
(a) thermal effect
More than 70% of the human body is water, water molecules by electromagnetic radiation friction with each other, caused by the body warming. Thermal effect refers to the electromagnetic radiation emitted by electromagnetic waves through the surface layer of the organism on the organism tissue "heating", due to the organism does not have this "heating" effect of countermeasures, the lack of corresponding heat dissipation mechanism, resulting in damage to the organization of the organism, seriously affecting the normal functioning of the body. This effect is mainly caused by high-frequency electromagnetic radiation. This effect is mainly influenced by high-frequency electromagnetic radiation, which acts on the organism, and is not easily seen on the outside of the organism when the radiation is not severe, but when the radiation is severe and can be seen on the organism, the organism has been severely damaged.
(2) non-thermal effects
The organs and tissues of the human body are present in the weak electromagnetic field, they are stable and orderly, once the interference of the external electromagnetic field, in the equilibrium state of the weak electromagnetic field disorders. The human body is repeatedly subjected to electromagnetic radiation, the central nervous system, immune system, endocrine system, reproductive system and other aspects of the function changes. Common diseases that may result include infantile deformities, tumors and leukemia. Non-thermal effects are mainly affected by low-frequency electromagnetic radiation, which can be generally categorized into physical non-thermal effects and chemical non-thermal effects, among which chemical non-thermal effects are extremely harmful to organisms.
(3) Cumulative effect
Thermal and non-thermal effects on the human body after the role of the human body has not yet had time to repair the damage to the human body before the re-exposure to electromagnetic radiation, the degree of damage will occur cumulatively, and in the long term, will become permanent lesions.
It should be noted that domestic and foreign experts and scholars on the biological effects of electromagnetic radiation research has been up to half a century. However, due to different factors such as the purpose of the study, methodology, and conditions (distance, time, and biological modeling of exposure to electromagnetic radiation sources), the results of the study and the viewpoints of the study are not consistent, and sometimes even diametrically opposed.
We usually refer to the band of electromagnetic radiation as the band of electromagnetic waves from ultra-long-wave to microwave, which is the main band that mainstream electrical appliances can emit.
Generally speaking, the intensity of large, small band of electromagnetic waves on the human body has the greatest impact, but must be added to a premise, is the length of time the electromagnetic wave exposure.
If the electromagnetic wave is compared to water, then the intensity can be compared to the flow of water, the band is compared to the flow rate, the length of time is universal, so it is easy to understand, we observe the impact of the water flow on the dam, it must be the flow of water is large, the flow rate is high, the long time of the water flow of the impact of the dam has a greater impact, leaving aside any of the factors to talk about the impact of the damage is one-sided.
So when we talk about the impact of electromagnetic radiation on the human body, it is necessary to synthesize the intensity, wavelength and duration of the three aspects to consider.
I would like to make one thing clear, that is, I personally tend to live in the electrical appliances issued by the electromagnetic radiation on the human body is influential!
Because, in the information I have contacted, almost all of the articles that say that the electromagnetic radiation from electrical appliances in life is harmless, said that the theoretical basis; and said that harmful, can cite experiments or research basis.
And some countries, such as the United States, Sweden, and the United Kingdom, have set the safety value of industrial frequency electromagnetic radiation at a very low number (0.2 or 0.4 microtesla), and explicitly require that children's activities must be below this value. In our country this value is 100 microtesla, and I am not in a position to prove that this value is not safe, but I don't think that anyone should want to live and work next to such a high level of electromagnetic radiation equipment.
Most of the electrical appliances in our lives are issued by the industrial frequency electromagnetic radiation, many people say that this electromagnetic radiation has no effect on the human body, but in fact, not so, this place we must make it clear that the intensity and duration, the intensity of large to a certain extent of the industrial frequency electromagnetic radiation as well as baked chicken fillet, long years of exposure to low-intensity electromagnetic radiation will be the same as the human body will bring about a certain change in the former, similar to a tsunami, the latter is similar to the human body to bring a certain change, and the latter will be similar to the human body to bring a certain change. The first one is similar to a tsunami, and the second one is similar to a water droplet.
Of course, we can't touch the grilled chicken fillet type of electromagnetic radiation, and we usually have access to a higher value of electromagnetic radiation usually not more than 50 micro Tesla (μT), which we don't have any feeling of under this kind of electromagnetic radiation. But our life will have a long time in contact with household appliances or office equipment, such as electric blankets, computers, televisions, refrigerators, fish tanks to oxygen pumps, etc., the good thing is that this electrical equipment is not much closer to us, only cell phones, computers and electric blankets are close to some.
In many countries, near high-voltage lines is prohibited to build residential housing and public **** activities, or the price of houses built in these places will be very low. I personally measured, 10 kV about 30 meters of the electromagnetic radiation value of the place between 0.07-0.09 micro Tesla, even according to the standards of Sweden, the United States, this is also considered a safe range, but these countries still do such a regulation, see in fact they did not feel that they set the safety value of electromagnetic radiation may not be safe either.
Some cities in our country also wanted to set their own safety standards for electromagnetic radiation, for example, Beijing once wanted to set this standard at 1 microtesla, but immediately some scholars came out to oppose it and rejected the proposal. In the end, the proposal was not adopted, and it is not known whether the economic interests of all parties are involved in the game.
My advice to you is to stay away from high levels of electromagnetic radiation as much as possible, and if you have to be in close proximity to it, then try to shorten your exposure as much as possible.
Electromagnetic radiation can not be seen, touched, felt, and its damage is slow, hidden. The harm of electromagnetic radiation varies from person to person, some people in the stronger radiation field is not much effect, some people may have a great impact, some diseases may take a longer time to show.
For this reason, the elderly, children, pregnant women or patients with pacemakers, sensitive people to electromagnetic radiation and people working in an environment with excessive doses of electromagnetic radiation for a long time should take protective measures.
Here are a few commonly used methods of protection against electromagnetic radiation:
1, do not place the household appliances too centralized, so as not to expose themselves to excessive doses of radiation in the space. In particular, some easy to produce electromagnetic wave household appliances, such as radio, television, computer, refrigerator, etc. should not be centrally placed in the bedroom.
2, should try to avoid the direct emission of antennas in the area of the long stay.
3, a variety of home appliances, office equipment, cell phones, etc. should try to avoid prolonged use, while trying to avoid a variety of office equipment and home appliances at the same time.
4, the use of electrical appliances, the human body and electrical appliances should maintain a certain safety distance. The farther away from the appliance, the smaller the infringement of electromagnetic wave. Such as people and color TV distance should be 3 to 4 meters, and fluorescent tubes distance should be 2 to 3 meters, and the distance from the microwave oven at least 1 meter. Cell phone connection instant release of electromagnetic radiation is the largest, in the use of the head and cell phone antenna should try to make the distance farther, it is best to use the separation of the headset and microphone to answer the phone. Electric blankets are most damaging to pregnant women, children and the elderly, and should be used with caution.
5, conditional units and individuals can be equipped with radiation protection devices, such as: anti-radiation clothing, anti-radiation screen, anti-radiation curtains, anti-radiation glass, etc., electromagnetic radiation will maximize the blocking of the body outside.
With the development of electromagnetic technology, human life has undergone a profound change, electromagnetic technology to bring convenience to life at the same time also brings a threat. How to utilize the electromagnetic technology, protection against electromagnetic radiation pollution has become more and more important. The state should continue to improve the electromagnetic radiation related standards, strengthen the supervision, the relevant units of electromagnetic radiation to be taken seriously, strengthen publicity and education, so that people understand the basic principles of electromagnetic radiation, master the relevant knowledge of protection, to avoid electromagnetic radiation damage.
Electromagnetic radiation can cause discomfort or even serious harm to the human body, but does not mean that as long as there is electromagnetic radiation will be a big disaster.
At the beginning of the article, we said that in today's society, we all live in electromagnetic radiation. Electromagnetic radiation as a physical phenomenon, has always existed in nature. From the point of view of human function, only when the radiation is excessive, it will cause harm to the body. Daily life in the necessary "anti-radiation" knowledge is indispensable, but there is no need to fear of electromagnetic radiation.
The word radiation, sounds dangerous, however, the real meaning of radiation, to a large extent, was misinterpreted and exaggerated, it is in fact only "dispersed around the" meaning, so the electromagnetic wave is known as electromagnetic radiation, because they are charged particles from the "radiation". "out. In the electromagnetic spectrum, according to the wavelength from long to short can be divided into radio waves, microwaves, infrared, visible light (red, orange, yellow, green, blue, indigo, violet), ultraviolet, X-rays, gamma rays.
Different electromagnetic waves have different ways of radiation, and most of the electromagnetic waves we come into contact with in our daily lives are not very strong.
The vast majority of radiation does not actually harm the human body and is not something to worry about. It is a particular type of radiation, called ionizing radiation, that poses a real risk of causing cancer.
According to the energy level, radiation can be divided into two categories: ionizing radiation and non-ionizing radiation. Ionizing radiation is high in energy and can directly damage DNA, causing genetic mutations and therefore a cancer risk, while non-ionizing radiation is low in energy and is not enough to damage DNA, and therefore theoretically has no cancer risk.
Non-ionizing radiation is not high enough to cause a direct effect on cells and DNA, and theoretically does not cause cancer. And scientists have actually done a lot of research, and the conclusions are clear: exposure to these radiations does not increase the likelihood of cancer.
In 2011, the International Agency for Research on Cancer (IARC) classified electromagnetic radiation (cell phone signals) as a "probable carcinogen", which caused a lot of panic. Some articles on the Internet say that long-term cell phone use may cause brain tumors.
What is the truth?
No need to panic.
First of all, "probable carcinogen" does not mean that it causes cancer, in fact, the exact meaning is "some people say that it may cause cancer, but it can not be proved, it is worth to continue to pay attention to".
The IARC's "probable carcinogens" include everything from coffee.
How did cell phones end up in the "probable carcinogen" pit?
The main reason for this is a Swedish study: if you talk on your cell phone for more than half an hour a day for more than 10 years, you are slightly more likely to get a glioma (a subspecies of brain tumor) than if you don't use your cell phone (from 0.005% to 0.016%).
There's actually a lot of controversy in the scientific community about this study, mainly because of its poor experimental design. For example, its data sources were not objectively recorded, but relied on everyone to fill out their own forms and report. But the question is, can people really remember exactly how long they've been using their cell phones every day for the past 10 years?
Although many scientists don't buy it, the data is out there, and the IARC has given cell phones the title of "probable carcinogen" as an insurance policy, which means, "If you believe it, you can have it, if you don't believe it, you can't have it, and we'll talk about it when there's more data available.
This is the first time I've seen a computer with the same name.
Later, the World Health Organization and the International Commission on Non-Ionizing Radiation Protection both made in-depth studies, and there is no evidence to prove that non-ionizing radiation on human health of the substantial harm, in addition to heat. The so-called neurasthenia and other symptoms are mostly psychological. Long-term animal experiments also side evidence, the animals placed in the environment of electromagnetic radiation higher than the surrounding communications base stations, and did not find any effect on them.
Of course, the science is not complete, we just stand on the current level of understanding, concluded that non-ionizing radiation has no other effects than heat. It is possible that other potential hazards may be discovered later, but at the very least, there is no scientific basis, both theoretical and practical, for this.
The debate on whether electromagnetic radiation is harmful to people has never stopped, the more credible argument is that strong radiation is harmful to the human body, and therefore the general intensity of electromagnetic radiation should have an impact on human health, but how much of the intensity of the impact of the health of the standard, the scientific community has not been determined, the international community in order to take precautionary measures to prevent the mandatory formulation of this standard.
China's electromagnetic radiation safety standards are: 8 microwatts / square centimeter, electrical appliances sold on the market need to comply with this standard, and therefore do not have to worry too much about the problem of radiation. So what is the intensity of electromagnetic radiation of our common household appliances? It should be noted that different specifications and brands of the same appliances, the intensity of their radiation is not the same, in addition to the same degree of radiation on different groups of people are not the same, usually pregnant women and the fetus is more vulnerable, the most likely to be affected, and therefore still need to pay attention to avoid electromagnetic radiation. -20 Introduction)
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