Electromagnetic radiation is invisible and intangible. The equipment that generates electromagnetic radiation is mostly used in people's daily life, such as mobile phones, electric blankets, induction cookers, medical equipment, electronic instruments, etc., which work at different wavelengths. Electromagnetic waves fill the space, and when the electromagnetic radiation intensity exceeds the limit that the human body can bear or the equipment can tolerate, electromagnetic pollution is generated. Therefore, electromagnetic pollution refers to various electromagnetic interferences caused by electromagnetic radiation to the environment and harmful to the human body.
Electromagnetic pollution affecting human living environment can be divided into two categories: natural electromagnetic pollution and artificial electromagnetic pollution.
(1) NaturalNatural electromagnetic pollution is caused by certain natural phenomena. The most common is lightning. In addition to direct damage to electrical equipment, aircraft, buildings, etc., lightning can also cause severe electromagnetic interference in a wide range of frequencies from a few thousand Hz to several hundred MHz. Electromagnetic interference can occur due to volcanic eruptions, earthquakes, and magnetic explosions caused by sunspot activity. Natural electromagnetic pollution is extremely irritating to short-wave communications.
(2) ArtificialMan-made electromagnetic pollution includes:
1. Pulse discharge. For example, a spark discharge generated when a large current circuit is cut off has a large transient current and generates a strong electromagnetic force. It is essentially the same as lightning, but with a small impact area.
2. Power frequency alternating electromagnetic field. For example, electromagnetic fields in the vicinity of high-power motors, transformers, and power lines do not radiate outward in the form of electromagnetic waves, but cause severe electromagnetic interference in the near-field region.
3. Radio frequency electromagnetic radiation. For example, radio, radio, television, microwave communication and other radio frequency equipment radiation, wide frequency range, large impact area, can harm the staff in the near field. Radio frequency electromagnetic radiation has become a major factor in the electromagnetic pollution environment.
Three sources of pollution(1) High-frequency induction heating equipment such as induction hardening, high-frequency welding, and high-frequency melting equipment.
(2) High-frequency medium heating equipment such as a plastic heat sealing machine, a high-frequency drying processor, and a medium heating coupling.
(3) Short-wave ultrashort wave therapy equipment.
(4) Radio broadcast communication.
(5) Microwave heating and launching equipment.
Four hazards 1. Electromagnetic radiation pollution endangers human healthIn the radio frequency electromagnetic field, the biological organism will generate thermal, non-thermal and cumulative effects due to the absorption of radiant energy. When the radiation intensity of the radio frequency electromagnetic field is controlled within a certain range, it can have a good effect on the human body, such as treatment with a physiotherapy instrument. . However, when it exceeds a certain range, electromagnetic radiation has different degrees of influence on human visual system, immune function, cardiovascular system, endocrine system, reproductive system and genetics, central nervous system, etc., such as activation of proto-oncogenes. Inducing cancer is one of the causes of childhood leukemia. The direct consequence of multiple frequency electromagnetic waves, especially high-frequency waves and strong electromagnetic fields acting on the human body, is unconsciously causing people's energy and physical strength to diminish, causing disorder of the human circadian clock, reducing memory, thinking and judgment, and easily producing cataracts. , brain tumors, cardiovascular diseases, and women's abortions and infertility, and even cause cancer and other diseases.
2. Interference communication systemPoor management of electromagnetic radiation, high-power electromagnetic waves will interfere with each other in the regional environment, resulting in damage to the communication system or even serious accidents, such as missile mis-launch, aircraft crash, etc., causing unpredictable catastrophic consequences, if signal interference And damage, can directly affect the normal operation of electronic equipment, instrumentation, information error, control failure, communication is not smooth.
3. Initiating an explosion accidentHigh levels of electromagnetic induction and radiation can cause explosive control of explosive materials and electric explosive weapons, and accidental explosions occur. Electromagnetic radiation can also cause harmful substances, and high-level electromagnetic induction and radiation can cause accidental combustion of volatile liquids or gases.
Five protections 1. Establish and improve regulations and standards for prevention and control of electromagnetic radiation pollutionIn 1988, China formulated the Environmental Electromagnetic Wave Sanitation Standard (GB 9175--1988). This national standard is no longer suitable for the current situation of the electromagnetic environment. It is extremely urgent to formulate new electromagnetic radiation health standards.
In addition, China has not yet issued a formal standard for magnetic induction. The “standard limit†proposed by Shanghai Academy of Environmental Sciences is 100μT, which is actually only the “recommended value†of the State Environmental Protection Administration. This is the most relaxed "standard" in the world. According to this standard, even if people stand under the high voltage line of 500,000 volts, the magnetic induction will not exceed the standard. In the Shanghai Maglev project, if 100μT is used as the standard, there is no need to set up a protective belt at all.
2. Effective control of electromagnetic radiationReasonable industrial layout, so that electromagnetic pollution sources are away from dense areas of residents; improve electrical equipment; use electromagnetic radiation absorbing materials or devices in the near-field area; implement remote control and telemetry operations.
An effective way to control electromagnetic radiation pollution is to install an electromagnetic shielding device, which is a closed casing made of a metal material. When the alternating electromagnetic field is transmitted to the metal casing, the amplitude is attenuated, thereby reducing the harmful electromagnetic strength to an allowable range. Electromagnetic shielding is divided into active field shielding and passive field shielding. Other technologies such as high-frequency grounding, filtering technology, plant greening, and the use of electromagnetic radiation protection materials are also effective in controlling electromagnetic radiation pollution.
3. Strengthen individual protectionIn order to prevent electromagnetic radiation pollution, we should pay attention to the knowledge of electromagnetic radiation, and subjectively improve the awareness of self-protection, understand relevant national laws and regulations, and protect our health and safety from infringement.
(1) Keep the safe distance between the human body and office computers and household appliances. For example, the distance between the TV set should be 4~5m, the distance between the fluorescent tubes should be 2~3m, and the distance between the microwave oven should be at least 1m. Pregnant women and children should try to stay away from the microwave oven.
(2) It should avoid long-term operation of household appliances, office equipment, mobile phones, and avoid the simultaneous activation of multiple office and household appliances. The electromagnetic radiation released when the mobile phone is turned on is the largest, and it is better to use a separate earphone and a microphone to answer the call.
(3) Purchase daily household appliances with small electromagnetic radiation, such as wireless local telephone (PHS) and CDMA mobile phones; the same type of mobile phones, the built-in antenna type mobile phone is smaller than the external radiation of the antenna.
(4) The elderly, children and pregnant women are sensitive to electromagnetic radiation. When they are active in an environment with electromagnetic radiation, they should choose appropriate protective clothing to protect them. It is recommended that pregnant women should be protected in all aspects during pregnancy, especially in the first trimester of pregnancy. There is no chance of harm to electromagnetic radiation.
(5) Eat more foods rich in vitamin A, vitamin C and protein, such as carrots, animal livers, etc.; you can also drink green tea or eat ginseng, sputum and other health products to enhance the body's resistance and improve The ability to repair organ tissue.
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