Definition Electromagnetic wave pollution, also known as electromagnetic pollution or called radio frequency radiation pollution. It is characterized by the field force of the electromagnetic field and is closely related to the nature, power, density and frequency of electromagnetic waves. Due to the wide application of electronic technology, radio broadcasting, cell phones, television and microwave technology and other causes of rapid development and popularization, the power of radio-frequency equipment exponentially increased, electromagnetic radiation on the ground increased substantially. Has reached a level that can directly threaten human health. Electromagnetic pollution is a kind of invisible pollution, has become a public hazard of great concern to people, to the human society has brought the impact of the world has attracted the attention of countries, is listed as one of the environmental protection program.
Classification
Man-made electromagnetic pollution includes:
①Pulse discharge. For example, the spark discharge generated when cutting off a high-current circuit has a large transient current, which generates a very strong electromagnetism. It is essentially the same as lightning, except that the area of influence is smaller.
② Industrial frequency alternating electromagnetic field. For example, in the vicinity of high-power motors, transformers, and transmission lines and other electromagnetic fields, it does not radiate outward in the form of electromagnetic waves, but in the near-field area will produce serious electromagnetic interference.
3 radio frequency electromagnetic radiation. For example, radio broadcasting, television, microwave communications and other kinds of radio frequency equipment radiation, frequency range is wide, the impact of the region is also larger, can jeopardize the near-field area of the staff. Radiofrequency electromagnetic radiation has become the main factor in electromagnetic wave pollution of the environment.
Transmission mode
1 radio and television transmitting equipment, the main system of radio broadcasting communications, for the transmitter and relay stations around the radio and television and other departments.
2 Communications radar and navigation transmitting equipment communications, including short-wave transmitters, microwave communication stations, terrestrial satellite communication stations, mobile communication stations.
3 Industrial, scientific research, medical high-frequency equipment. This type of equipment to convert electrical energy into heat or other energy to be utilized, but accompanied by electromagnetic radiation generated and leaked out, causing environmental pollution in the workplace.
Industrial electromagnetic radiation equipment: mainly for high-frequency induction heating equipment, such as high-frequency quenching, high-frequency welding and high-frequency furnace, high-frequency melting equipment, etc., as well as high-frequency media heating equipment, such as plastic heaters, high-frequency drying and processing machines, high-frequency media heating coupling machine.
Medical electromagnetic radiation equipment: mainly for short-wave, ultra-short-wave physiotherapy equipment, such as high-frequency physiotherapy machine, ultra-short-wave physiotherapy machine, ultraviolet ray physiotherapy machine.
Scientific research electromagnetic radiation equipment: mainly for the electronic gas pedal and a variety of ultrasonic devices, electromagnetic cooker.
4 electromagnetic radiation interference in transportation systems, including: electrified railroads, light rail and electrified railways, rail trams, trackless
trams and so on.
5 Power system electromagnetic radiation, high-voltage transmission lines, including overhead transmission lines and underground cables, substations, including power plants and transformer power stations.
6 Household appliances electromagnetic radiation, there are microwave heating and transmitting equipment, including computers, monitors, televisions, microwave ovens, wireless phones and so on.
Electromagnetic pollution in family life closely related to people's daily lives, refers to a variety of electronic life products, including air conditioning units, computers, televisions, refrigerators, microwave ovens, karaoke machines, VCD machines, stereos, electric blankets, mobile telephones, etc., in the normal operation of a variety of different wavelengths and frequencies generated by the electromagnetic wave on the people's interference, the impact and harm.
The main hazards
As electromagnetic waves are colorless, tasteless, invisible, no trace, plus the pollution of neither any feeling, and everywhere, so scientists called "electronic garbage" or "electronic radiation pollution", which brings people The harm it brings to people cannot be underestimated. Mainly in the following three aspects:
(1) affect the normal work of electronic equipment
Modern science and technology increasingly tend to use large-scale and ultra-large-scale integrated circuits, circuit component density is extremely high, coupled with the use of the current for the micro-current, so that the signal power and the noise power is very little difference between the parasitic radiation may result in the electronic system or the electronic equipment of the wrong action or obstacles. On the other hand, the rapid development of the modern wireless communications industry, a variety of transmitter towers make the airwaves congested, seriously affecting all aspects of normal business. Starting from September 1996, there were frequent incidents of wireless paging stations interfering with the air communication frequency above 1.30 MHz at Beijing Capital Airport, and at 8:15 a.m. on February 20, 1996, the air-to-air channel was seriously interfered with, and 10 airplanes had to wait for their turn in the air, which resulted in the outgoing airplanes having to pull away from the flight time for 5 min to 15 min. The same incident occurred frequently in other parts of the country. In places where people are accustomed to think that the sky is as high as the birds fly, electromagnetic wave interference has brought great harm to people.
(2) Scientific research and facts show that electromagnetic waves are also extremely harmful to the human body
The harm of electromagnetic radiation on the human body is caused by the energy of electromagnetic waves. According to relevant experts, China's use of mobile electric
Talk of the emission frequency are between 800 to 1000 MHz, the radiation dose of up to 600 micro-watts, exceeding the national standard of more than 10 times, and excessive electromagnetic radiation will cause human neurasthenia, appetite, palpitations, chest tightness, dizziness and other "electromagnetic wave allergies "and even cause brain tumors. Electromagnetic wave pollution on the human body more examples of harm found, only the extent of its impact and the intensity of radiation and accumulation of time is related to the length of time, has not yet a larger scope to reflect, so it has not yet attracted widespread attention. Studies have shown that the pathogenic effect of electromagnetic waves with the increase in the frequency of magnetic field vibration increases, the frequency of more than 100,000 Hz or more, can pose a potential threat to the human body. Working and living in this environment for too long, the human body is subject to electromagnetic interference, so that the original electric field of the molecules in the body's tissues change, resulting in disorders of the ecological balance of the body. Some people who have been subjected to stronger or longer electromagnetic wave radiation, there have been pathological manifestations, mainly reflected in the nervous system and cardiovascular system. Such as fatigue, memory loss, insomnia, easily agitated, menstrual disorders, chest tightness, palpitations, white blood cells and platelets decreased or low, reduced immune function.
(3) may trigger the explosion of explosives or explosive mixtures of the risk of explosion
Some tall metal structures in specific conditions due to high-frequency induction will produce sparks discharge. This discharge not only give people different degrees of electric shock, but also may detonate dangerous goods, resulting in catastrophic consequences. This is a fire explosives production enterprises need to pay great attention to the problem.
(4) Electromagnetic radiation is one of the main triggers of cardiovascular diseases, diabetes, and cancerous mutations
(5) Electromagnetic radiation causes direct harm to the human reproductive system, nervous system and immune system
(6) Electromagnetic radiation is one of the triggering factors that cause pregnant women to suffer from miscarriages, infertility, teratogenicity and other pathologies
(7) Excessive electromagnetic radiation directly Impact on children's body tissues, bone development, leading to vision, liver hematopoietic function decline, serious cases can lead to retinal detachment
(8) electromagnetic radiation can make men's sexual function decline, women's endocrine disorders.
Pollution pathways
There are two ways of spreading the interference of electromagnetic waves:
One is conduction interference, which is the interference caused by the spread of electric current along the power line;
The other is radiation interference, which is caused by the emission of electromagnetic waves from the source of the emission of electromagnetic waves into the surrounding space.
In order to prevent and suppress electromagnetic wave interference, the main use of rational circuit design, filtering, shielding and other technical methods. Rational design of circuits is in a small space, reasonable arrangement of components and layout lines, can weaken the parasitic electromagnetic coupling, suppress electromagnetic interference. Filter is a line of resistance, inductance and capacitance, this network allows certain frequency signals to pass, while preventing other frequency signals to pass, the correct design and installation of filters can minimize electromagnetic interference. Shielding technology as a basic means of suppressing electromagnetic radiation has been widely used. The purpose of shielding
is to limit the radiant energy in a specific area, or to prevent the radiant energy into another specific area. Shielding materials is the key to shielding efficiency, the newly developed wave-absorbing materials have been introduced, it will open up a clean space for mankind to make contributions. The electromagnetic wave radiation pollution in addition to the use of the above technical methods to inhibit, but also other methods to reduce its harm, such as in the airports around the ban on the establishment of high-power wireless paging station, the frequent contact with radio frequency equipment staff to take good shielding protection measures, etc..
In short, with the development of science and production, the harm of electromagnetic radiation pollution has a tendency to deteriorate, the study of electromagnetic wave pollution hazards and protection has great practical significance.
Electromagnetic wave penetration
Because electromagnetic waves have wave-particle duality, wavelength and photon energy inversely proportional to the relationship between the shorter the wavelength of the photon energy is greater, the stronger the penetration. Such as high-energy X-rays can penetrate almost all non-metallic materials, and can even penetrate thin aluminum; and gamma rays can penetrate most metals. Some heavy metals can block electromagnetic wave penetration, such as lead.
Related cases
Also more than 20 years ago, after the popularization of home microwave ovens in the United States, some patients with pacemakers, often feel uncomfortable, and some pacemakers even failed to stop. Later, the scientists' research to make the truth come out, the reason is that "electromagnetic wave pollution" caused.
A few years ago, Russia's famous chess master Nikolai Kedkov and a computer game, after winning three games, unexpectedly suddenly by the computer released a strong current knocked down. An investigation confirmed that it was not a computer hardware leakage, nor was the software designed to kill the program, the cause of death is again invisible electromagnetic waves.
There are reports that workers who spend more than six hours a day in front of their computers are prone to a condition known as "VOT". The disease refers to the long-term viewing of video terminals and make some parts of the body lesions of the general term. Its main symptoms are: visual dysfunction; neck, shoulder, wrist dysfunction; vegetative nerve dysfunction, etc.; in addition to menstrual disorders, miscarriage and other women's diseases and other skin diseases. The reason for this is also caused by electromagnetic radiation.
Mobile phones and walkie-talkies, but also a high-frequency electromagnetic wave pollution emission source, every call on the launch of an electromagnetic wave. Scientists believe that the intensity of electromagnetic wave radiation from cell phones generally exceeds the prescribed standards by 4 to 6 times, and individual types even exceed nearly 100 times. China's Electromagnetic Radiation Testing Center and Xiamen Evergreen Source Radiation Protection Institute after two years of tracking and testing has confirmed that the current use of cell phones in China will produce radiation hazards to the human body.
Pollution prevention
To mitigate the harm of electromagnetic wave pollution, there are many easy-to-operate measures.
The general principle of two:
One, due to the need to work can not be far from the source of electromagnetic wave emissions, must take the shielding protection approach;
Two, try to increase the distance between the human body and the source of emissions.
Because the impact of electromagnetic waves on the human body, and the size of the transmitter power and the distance from the transmitter source is closely related to its harm
degree of the transmitter power is directly proportional to the square of the distance inversely proportional. Cell phones as an example, although its transmitting power is only a few watts, but because of its transmitting antenna is very close to the head, the actual intensity of radiation, but equivalent to the distance of tens of meters away from a few hundred kilowatts of broadcasting antennae are subject to the intensity of radiation. The good thing is that people use a very short period of time, a moment will not show obvious symptoms of harm; but the use of a long time, radiation-induced symptoms will be gradually exposed to excessive radiation will make the cellular activity and division of abnormalities, and the possibility of carcinogenicity.
In view of this, we should consciously take measures in our daily lives to reduce the harm of electromagnetic wave pollution. Such as in the machine room and other electromagnetic wave intensity of the place of work, should pay special attention to the rest of the work period, can be appropriate to stay away from the electromagnetic field of outdoor activities; in the use of cell phones to make the antenna as far as possible away from the human body, in particular the head, and try to minimize the time of each call; household appliances should not be placed in a centralized manner, the distance of watching TV should be kept at 4 to 5 meters, and pay attention to the window ventilated; microwave ovens, Refrigerator should not be close to the use; teenagers try to play fewer video games; electric blanket preheating, sleep should be cut off the power supply, children and pregnant women do not use electric blankets; usually should eat more fresh vegetables and fruits to enhance the body's ability to resist electromagnetic wave pollution.
One, keep the distance. Distance from the television should be the size of the screen multiplied by 6, and the distance from the microwave oven should be 2.5 to 3 meters, away from the high-voltage power lines 0.5 million volts / meters away from the general regarded as a safe area.
Two, reduce contact. Regular use of computers, every hour of work should take a quarter of an hour break, and work up to 32 hours a week.
Three, improve the environment. Pay attention to air circulation, temperature, humidity should be moderate, household appliances are best not placed in the bedroom.
Four, individual protection. Pregnant women, children, frail and sick people, allergic to electromagnetic radiation, long-term electromagnetic pollution in the environment exceeding the standard, should choose to use their own protective products.
Fifth, less use of cell phones. To minimize the use of cell phones, walkie-talkies and cordless phones, must be used should be long and short; do not often hang the phone on the body.
Sixth, less use of electric blankets. Electromagnetic wave pollution of electric blankets is more serious, prolonged use of electricity is harmful to the human body, cold weather must be used, it is recommended to cut off the power supply immediately after the warmth of the electric blanket, in order to reduce electromagnetic wave pollution.
Seven, the use of shielding to reduce electromagnetic wave pollution. To produce electromagnetic pollution facilities, can be used to shield, reflect or absorb electromagnetic wave shielding materials, such as copper, aluminum, steel, polymer film.
Eight, according to the characteristics of electromagnetic wave attenuation with distance, in order to reduce the harm of electromagnetic waves on the residents, should be made to emit electromagnetic power, may produce strong electromagnetic wave workplaces and facilities, such as television stations, radio stations, radar communication stations, microwave transmission stations, etc., as far as possible, located in the suburbs away from the residential areas of the counties or areas with high terrain. Must be set up in the city, neighboring residential areas and residents often activities within the scope of the facilities, such as substations, etc., should be maintained with a certain safety protection distance between the residential areas to ensure that their boundaries meet the requirements of environmental electromagnetic wave health standards. At the same time, the source of electromagnetic wave radiation need to choose to shield, reflect or absorb electromagnetic waves of copper, aluminum, steel and other metal wires or polymer film and other materials made of items for electromagnetic shielding, electromagnetic radiation energy is limited to the required space.
Nine, high voltage, especially ultra-high voltage transmission lines should be far away from homes, schools, sports stadiums and other crowded areas. The use of computers, should choose a low-radiation monitor, and keep the human body and the display of the front of the distance of not less than 75cm, the side and the back of not less than 90cm, it is best to install shielding devices.
Ten, should strictly control the density of mobile communication base stations, to ensure that a variety of mobile communication base station antennae set up in urban areas higher than the surrounding buildings, in kindergartens, schools, hospitals and other buildings around a certain range shall not be established within a certain range of transmitting antennae.
Eleven, in order to reduce the family indoor electromagnetic pollution and its harmful effects, should often be ventilated to the room, keep the indoor air clear. Scientific use of household appliances: for example, when watching TV or home theater, listening to the combination of audio, should be kept at a distance, and to avoid all kinds of electrical appliances turned on at the same time; the use of computers or video games should not be used for too long a period of time, and so on.
Twelve, the use of cell phone calls, try to reduce the duration of the call; cell phone antenna top should be as far as possible away from the head, as far as possible to stretch the antenna; in the cell phone calls on the headset, and so on.
Thirteen, in addition, you can take a certain amount of vitamin C every day or eat more vitamin C-rich fresh vegetables, such as chili peppers, persimmon peppers, parsnips, cauliflower, spinach, etc.; more fresh fruits, such as citrus, jujube and so on. Diet also pay attention to eat more food rich in vitamin A, C and protein, such as tomatoes, lean meat, animal liver, bean sprouts, etc.; often drink green tea. These dietary measures, to a certain extent, can play an active role in preventing and mitigating the harm caused by electromagnetic radiation on the human body.
Fourteen, electromagnetic radiation is nearly three or four decades to be recognized as a new environmental pollution, now people are still in the electromagnetic radiation is still in the stage of understanding and research. Because it can not see, touch, not easy to detect, so it is easy to cause people's misgivings. In addition, some reports on electromagnetic radiation are not very objective and lack of science, leading to unnecessary misunderstanding and panic. Generally speaking, to determine whether electromagnetic radiation causes pollution to the living environment, should be from the intensity of electromagnetic wave radiation, the main direction of radiation, the distance from the source of radiation, duration and other aspects of comprehensive consideration. Therefore, in the strengthening of electromagnetic protection at the same time, electromagnetic pollution should also take a scientific attitude, objective analysis, serious treatment, must not be cloudy, irresponsible blind exaggeration, resulting in confusion of people's understanding. Of course, with the development of science and technology, people's understanding of electromagnetic pollution and its harm will gradually deepen, many mysteries will eventually be unraveled. Electromagnetic environmental standards and related regulations. In order to control the pollution of the environment by electromagnetic wave in modern life and to protect people's health, the Ministry of Health of China promulgated the Environmental Electromagnetic Wave Health Standard (GB9175-88) on December 22, 1989, which stipulates that the limit value of the environmental electromagnetic wave intensity in the residential area should be less than lOV/m for the long, medium and short waves, and 5V/m for the ultra-short waves, and 10μW/cm2 for the microwaves. μW/cm2. China's relevant departments have also formulated the "TV tower radiation health protection distance standards", the State Environmental Protection Administration has also promulgated the "electromagnetic radiation environmental protection management measures".
In response to the development of mobile communications, the Beijing Municipal Bureau of Environmental Protection promulgated on February 17, 2000 the "Beijing Mobile Communication Construction Project Environmental Protection Management Regulations" (for trial implementation), the first of its kind in China to regulate electromagnetic pollution, in order to regulate the construction and operation of mobile communication stations and to prevent them from causing electromagnetic pollution to the environment. The provisions of the regulations clearly can produce electromagnetic radiation of mobile communication stations (stations) in the construction before the implementation of environmental protection approval procedures, and to handle environmental acceptance approval, by the environmental protection department's monitoring, the local power density in line with the national "Electromagnetic Radiation Protection Provisions" in the frequency in the range of 20 MHz ~ 3000 MHz, irradiation export limit of the power density in the 40 μW/cm2 this standard, before they can formally Put into use, greater than this standard must be deactivated or rectified; the construction of cellular mobile communication base stations to predict the distribution of user density before the use of the best frequency multiplexing to minimize the number of base stations; in the construction of mobile communication stations on residential buildings (stations), prior to the property rights of the building unit or the property management unit must be consulted by the residents living in the views of the residents; wireless paging communications, trunking communications antenna minimum allowable height of not less than 40m Cellular mobile communication base station outdoor antenna generally shall not be less than 25m, transmitting antenna within 50m of the direction of the main shot, the direction of the non-main shot within 30m, generally shall not be built higher than the antenna hospitals, kindergartens, schools, residential and other buildings; construction units should be in the installation of the above types of antennas to set the electromagnetic radiation warning signs.