electromagnetic radiation is the phenomenon that electromagnetic energy propagates through space in the form of electromagnetic waves, and its propagation speed is what people usually call the speed of light. Electromagnetic radiation can be arranged into several frequency bands according to its wavelength and frequency to form electromagnetic spectrum. The higher the frequency, the greater the quantum energy of the radiation, and the stronger its biological function.
electromagnetic radiation sources can be divided into natural electromagnetic radiation sources and artificial electromagnetic radiation sources (high-frequency induction heating equipment, high-frequency medium heating equipment, short-wave and ultrashort-wave physiotherapy equipment, microwave emitting equipment, radio broadcasting and communication and other radio frequency equipment). Lightning, sunspot activity and cosmic rays all produce electromagnetic radiation, which is a natural electromagnetic radiation source; The artificial electromagnetic radiation sources mainly include all kinds of radio equipment, such as mobile phones, walkie-talkies, indoor wireless phones, radio and television transmitters, microwave and satellite communication devices, radars, radio remote controllers, etc., as well as industrial, scientific and medical equipment, such as microwave ovens, high-frequency eye protection lamps, medical magnetic vibration equipment, helium arc welding machines, radio-frequency electric heaters, high-frequency heat bonding machines, AC high-voltage transmission lines, transfer switches and motors. Electromagnetic radiation is caused by electromagnetic emission. It can be said that all electrical appliances will produce electromagnetic radiation.
second, the harm of electromagnetic radiation
electromagnetic pollution has been recognized as the fourth largest public hazard after air pollution, water pollution and noise pollution. The United Nations Human Environment Conference listed electromagnetic radiation as one of the main pollutants that must be controlled. According to foreign data, electromagnetic radiation has become one of the pathogenic sources that endanger human health. In 1998, the World Health Organization listed five major effects of electromagnetic radiation on human body: < P > 1. Electromagnetic radiation is the main cause of cardiovascular disease, diabetes and cancer mutation;
2. Electromagnetic radiation harms human reproductive system, nervous system and immune system;
3. Electromagnetic radiation is the inducing factor of abortion, infertility and teratoma in pregnant women.
4. Electromagnetic radiation directly affects children's development and bone marrow development, resulting in decreased vision, retinal detachment and decreased liver hematopoietic function;
5. Electromagnetic radiation can cause endocrine disorder and menstrual disorder in women.
third, the knowledge of electromagnetic radiation protection of common electrical appliances
(1) mobile phone
1. When answering the phone, it is best to put the mobile phone away from your body and then put it in your ear to talk. In addition, try not to chat with your mobile phone, and be careful not to put your mobile phone on the pillow when you sleep.
2. Don't hang your mobile phone on your chest. Studies show that hanging your mobile phone on your chest will have a certain impact on your heart and endocrine system. Even in the standby state with less radiation, the electromagnetic wave radiation around the mobile phone will cause harm to the human body. People with cardiac insufficiency and arrhythmia should pay special attention not to hang their mobile phones on their chests.
3. Mobile phone users should try to keep their mobile phones away from their waist and abdomen, and don't hang them around their waist or put them in their coat pockets. When the user is in the office, at home or in the car, it is best to put the mobile phone aside. When you go out, you can put your mobile phone in your purse, which is far away from your body. Using headphones to answer mobile phones can also effectively reduce the influence of mobile phone radiation. Call as little as possible, use headphones as much as possible, and keep talking for no more than 3 minutes.
(2) computer
1. Put a few pots of cactus next to the computer, which can effectively absorb radiation.
2. Drink 2 ~ 3 cups of green tea and eat an orange every morning. If you are not used to drinking green tea, chrysanthemum tea can also play a role in resisting computer radiation and regulating your body function. Spirulina and sea buckthorn oil also have anti-radiation effects.
3. After using the computer, many particles of electromagnetic radiation will be absorbed on your face. Wash your face with clean water in time, which will reduce the radiation exposure by more than 7%.
4. When operating the computer, it is best to install a computer-specific color filter on the display screen to reduce the harm of radiation, and do not put any metal objects indoors to avoid the re-emission of electromagnetic waves. When using a computer, it is necessary to adjust the brightness of the screen. Generally speaking, the greater the brightness of the screen, the stronger the electromagnetic radiation, and vice versa. However, it should not be too dark, so as not to affect the effect because of the low brightness, and it is easy to cause eye fatigue.
5. You should buy new computers as much as possible, and don't use old computers. The radiation of old computers is generally severe, which is generally 1 ~ 2 times that of new computers at the same distance and with the same model.
6. computer placement is very important. Try not to let the back of the screen face people, because the computer has the strongest radiation on the back, followed by the left and right sides, and the front of the screen has the weakest radiation. The distance should be at least 5 ~ 75 cm, which can reduce the harm of electromagnetic radiation.
7. Pay attention to indoor ventilation. Scientific research has confirmed that the computer screen can produce a carcinogen called dibenzofuran bromide. Therefore, it is best to install a ventilator in the room where the computer is placed.
8. Try to avoid being in front of the computer for more than 3 hours, and take a break in between.
(3) induction cooker
1. Start with the pot selection. The ideal special cooker for induction cooker should be mainly made of iron and steel products, because this kind of ferromagnetic material will match the heating load (cooker and cooker) with the induced eddy current during the heating process, with high energy conversion rate and relatively less magnetic field leakage. However, ceramic pot, aluminum pot, etc. can't achieve this effect, and the threat to health is even greater.
2. Pay attention to keeping a distance from the induction cooker as far as possible when using, and don't get too close. The precautions when using an induction cooker and a microwave oven are similar. The closer you get, the easier it is to be radiated. Usually, it is safer to keep a distance of more than 2 cm from the induction cooker.
3. Don't use the induction cooker for too long. If you often use the induction cooker for a long time, you should choose a metal partition as far as possible. Because under normal circumstances, if the induction cooker is placed under the metal partition, the electromagnetic radiation is obviously low, the isolation design is not good, or the induction cooker is placed directly on the desktop, the radiation will increase a lot accordingly. This also requires us to choose brand-name products with quality assurance and reasonable and safe design when buying induction cookers. An important part of buying an induction cooker is to ask the seller for the test report of electromagnetic induction intensity, and compare and choose the products with low field strength through this report.
4. The supporting facilities in the kitchen are also very important. If conditions permit, you can prepare an electromagnetic apron made of stainless steel fiber and a pair of gloves to prevent electromagnetic radiation. These small preparations can also make you safer in the kitchen.
(4) Other household appliances
1. Refrigerator-When the refrigerator is working, the magnetic field released by the cooling pipeline at the back side or below is dozens or even hundreds of times higher than that in front. Too much dust in the radiator will also have an impact on electromagnetic radiation, and the more dust, the stronger the radiation.
protection: don't put the refrigerator in the living room and other places where people often stay. Try to avoid getting close to the refrigerator when it is working. Always use a vacuum cleaner to suck the dust off the radiator pipe.
2. microwave oven-it uses the thermal effect of microwave to heat or cook food by vibrating water molecules in food. The magnetic field at a distance of 15 cm from the microwave oven is 1-3 milligauss (MG), which is the strongest among all kinds of household appliances. It can induce cataracts, lead to brain abnormalities, and also affect reproductive capacity. Protection: Choose products from regular manufacturers. When the microwave oven is working, it is best not to be in the same room with it; When you stop working, open it for a minute or two. It's best to use a protective cover.
3. Electric blanket-Due to close contact with human body for a long time, resting cells will be exposed to electromagnetic radiation for a long time, thus causing health disorders. According to the test report, the rate of abnormal phenomena such as abortion in pregnant women who use electric blankets is higher than that in pregnant women who do not use electric blankets. Protection method: choose qualified products from regular manufacturers. Shorten the use time, preferably before and after going to sleep and getting up, and avoid staying up all night. After a certain number of years of use, it is necessary to discard the old and replace it with a new one in time. Pregnant women had better not use it.
4. TV sets-TV sets should not be too concentrated with other electrical appliances to expose themselves to the danger of excessive radiation; The distance between the TV and people should be at least 2 meters away, and should not be too close to the screen; Television and other electrical appliances are best not to be placed in the bedroom.