Open Categories: Physics, Radiation, Radiation Hazards, Electromagnetic Spectrum, Human Body Protection
Contents
Nouns Hazards of Electromagnetic Radiation on the Human Body Regulations for Protection against Electromagnetic Radiation Preventive Recommendations on Electromagnetic RadiationEnglish Name: electromagnetism radialization
Nomenclature
Electromagnetic radiation is composed of space *** with the transfer of electrical and magnetic energy, and the energy is generated by the movement of charge; for example, is transmitting signals from the radio frequency antenna issued by a mobile charge, it will produce electromagnetic energy. The electromagnetic "spectrum" includes all kinds of electromagnetic radiation, from very low frequency to very high frequency. In between are radio waves, microwaves, infrared, visible and ultraviolet light. The general definition of the radiofrequency portion of the electromagnetic spectrum refers to radiation with frequencies ranging from about 3 kHz to 300 GHz. The energy derived from electromagnetic radiation depends on the frequency - the higher the frequency, the greater the energy. X-rays and gamma rays, which are extremely high in frequency, can generate large amounts of energy and are capable of destroying the molecules that synthesize human tissue. In fact, X-rays and gamma rays are so energetic that they can ionize atoms and molecules and are therefore classified as "ionizing" radiation. Although these two types of radiation are used for medical purposes, excessive exposure to them can be detrimental to health. x-rays and gamma rays produce electromagnetic energy, which is different from that produced by radiofrequency (RF) transmitting devices. Electromagnetic energy from radiofrequency devices belongs to the lower frequency end of the spectrum and cannot break the chemical bonds that hold molecules together, so it is classified as "non-ionizing" radiation. Where does electromagnetic radiation come from? There are many sources of electromagnetic radiation. The human body is full of electrical and magnetic energy from both natural and man-made sources of radiation; lightning is an example of a natural source of radiation. Artificial sources of radiation include microwave ovens, radios, television transmitters and satellite communication devices.
Harm of electromagnetic radiation on the human body
November 22, 2000 at the Great Hall of the People in Beijing, the Fifth National Science Congress statistics show that the country's annual birth of more than 20 million newborns, close to 1.2 million for the defective children, experts pointed out that the factors that lead to defects in infants, electromagnetic radiation, the greatest harm.
Electromagnetic radiation is caused by pregnant women miscarriage, infertility, teratology and other pathologies predisposing factors.
1 to 3 months for the embryonic period, subjected to strong electromagnetic radiation may cause limb defects or deformities.
4 to 5 months of fetal formation, electromagnetic radiation may cause Chilean incomplete, or even cause dementia.
June to October for the formation of the fetus, electromagnetic radiation may lead to low immune function, after the birth of the system is weak, poor resistance.
Electromagnetic radiation protection regulations
1 General
1.1 In order to prevent electromagnetic radiation pollution, protect the environment, protect public health, and promote the development of legitimate practices accompanied by electromagnetic radiation, the formulation of these regulations.
1.2 These regulations shall apply to all units or individuals, all facilities or equipment within the territory of the People's Republic of China*** and the State of China that generate electromagnetic radiation pollution. However, the protection limits of these regulations do not apply to medical or diagnostic exposures arranged for patients.
1.3 The range of protection limits in this regulation is 100KHZ ~ 300GHZ. the relationship between protection limits and frequency is shown in the following figure.
1.4 The protection limits in this regulation are the upper limit of the acceptable level of protection and include the total value of various possible electromagnetic radiation contamination.
1.5 All units or individuals generating electromagnetic radiation pollution, should be based on the "can reasonably achieve as low as possible" principle, efforts to reduce the level of electromagnetic radiation pollution.
1.6 All units or departments that generate electromagnetic radiation pollution, can develop their own management limits (standards), each unit or department's management limits (standards) should be more stringent than the limits of this provision.
2 electromagnetic radiation protection limits
2, 1 basic limits
2, 1.1 Occupational exposure: in the daily 8H work period, any continuous 6MIN by the whole body average of the specific absorption rate (SAR) should be less than 0, 1W/KG.
2, 1.2 public exposure: in a day 24H, any continuous 6MIN by the whole body average of the specific absorption rate (SAR) should be less than 0, 1W/KG.
2, 1.2 public exposure: in a day 24H, any continuous 6MIN by the whole body average of the specific absorption rate (SAR). Specific Absorption Rate (SAR) should be less than 0.02W/KG.
2.2 Export Limits
2.2.1 Occupational Exposure: In the 8H working period every day, the average value of the field parameters of the electromagnetic radiation field in any consecutive 6MIN should meet the requirements of Table 1.
Table 1 Occupational Exposure Export Limits Frequency Range MHz Electric Field Strength V/m Magnetic Field Strength A/m Power Density W/m2
0.1~3 87 0.25 (20)1)
3~30 150/ 0.40/ (60/f) 1)
30~3000 (28)2) (0.075)2) 2
3000~15000 (0.5)2) (0.0015)2) f/1500
15000~30000 (61)2) (0.16)2) 10
Note: 1) This is the equivalent value of a plane wave for comparison.
2) For reference, not as a limit value; f is the frequency in the table, the unit is MHz; the data in the table has been rounded.
2, 2, 2 public exposure: in 1 day 24H, the parameters of the ambient electromagnetic radiation field in any consecutive 6MIN within the average value should meet the requirements of Table 2.
Table 2 public exposure derived limits Frequency range MHz Electric field strength V/m Magnetic field strength A/m Power density W/m2
0.1 ~ 3 40 0.1 (40)1)
3 ~ 30 67/ 0.17/ (12/f)1)
30 ~ 3000 (12) 2) (0.032)2) 0.4
3000~15000 (0.22/)2) (0.001)2) f/7500
15000~30000 (27) 2) (0.073) 2) 2
Note: 1) This is the equivalent value of a plane wave for comparison.
2) For reference, not as a limit value; f is the frequency in the table, unit is MHz; the data in the table has been rounded.
2, 2, 3 for a radiator emits several frequencies or the existence of multiple radiators, the field parameters of electromagnetic radiation field in any continuous 6MIN within the average value of the sum of the field, should meet the formula (1): where: the ith radiator j frequency band radiation emission level; corresponds to the j splash of the electromagnetic radiation prescribed exposure limit. 2, 2, 4 for pulsed electromagnetic waves, in addition to meet the above requirements, its instantaneous peak value shall not exceed 1000 times the limit values listed in Table 1.2.
2, 2, 5 in the frequency of less than 100MHZ in the industrial, scientific and medical radiation equipment near the occupational workers can be less than 1.6A / M magnetic field of 8H continuous work.
May 8, 1999 closing of the national electromagnetic radiation environmental pollution sources of the status quo: radio and television transmitting equipment *** 10,235, with a total power of 1.3 million kilowatts; industrial and scientific and medical equipment *** 15,335, 3 Earth satellites, Big Brother base stations totaling nearly 10,000; aerial spiderweb like high-voltage transmission lines, etc. are emitting leakage of electromagnetic waves to the outside. We are living in a huge microwave oven.
Preventive Recommendations on Electromagnetic Radiation
Preventive Recommendations on Electromagnetic Radiation - Extremely Low Frequency Electromagnetic Fields (Preventive Recommendations on Extremely Low Frequency Electromagnetic Fields from High Voltage Lines, Nuclear Magnetism*** Vibration, Electrified Railroads, Welding, Electric Sewing, etc.)
The WHO International Agency for Research on Cancer (IARC) and WHO Thematic Working Groups have evaluated that Extremely Low Frequency (>0Hz-100kHz) Magnetic Fields are associated with the presence of children's blood pressure. 100kHz) magnetic fields are associated with childhood leukemia and brain cancer, and the risk of childhood leukemia increases twofold when exposure to industrial frequency (50/60Hz) magnetic fields exceeds 0.3μT or 0.4μT. According to WHO statistics, about 1-4% of children are chronically exposed to industrial frequency magnetic fields with intensities greater than 0.3μT. Although the epidemiological data of the population and laboratory research data do not yet prove the existence of a causal relationship between IFMF and childhood leukemia, the WHO emphasizes in its newly published (2007) monograph on very low frequency electromagnetic fields for environmental health criteria that although the mechanism of biological effects of low-level ambient electromagnetic radiation has not yet been elucidated, it cannot be ruled out that low-intensity ambient electromagnetic radiation is capable of producing harmful health effects. At the same time, due to the ubiquity of electromagnetic radiation, almost everyone in the world is exposed to electromagnetic radiation, so even if its impact on human health is very mild, it will have a huge impact on human public **** health; and if some of these health effects are irreversible (such as tumors), then the economic health losses caused by the loss of life will be very painful.
WHO believes that appropriate measures should be taken to prevent known health hazards to the public from very low frequency electric and magnetic fields, in view of the existence of a certain degree of scientific uncertainty in the study of the health effects of electromagnetic radiation, WHO believes that countries in the development of preventive strategies against electromagnetic radiation should be taken into account in the electric power industry's significant contribution to society and the economy, should be used to low-cost precautions should be taken, and should not be subjective The WHO believes that countries should take into account the enormous contribution of the power industry to society and the economy when formulating preventive strategies against electromagnetic radiation, and should adopt low-cost preventive measures rather than subjectively lowering exposure limits to a degree that is not in accordance with scientific laws. (The following is translated from the WHO Environmental Health Criteria 2007 Monograph - Extremely Low Frequency Electromagnetic Fields) The WHO recommends the following:
1. Decision makers in all countries should develop guidelines for the public and occupationally exposed populations on exposure to extremely low frequency electric and magnetic fields; the International Exposure Guidelines are the best available;
2. Decision makers should develop plans for protection against extremely low frequency electromagnetic fields, and conduct testing of electromagnetic radiation from a variety of sources to ensure that the public is protected against such fields and to ensure that the public is protected against them. Electromagnetic radiation from all sources should be tested to ensure that the public and occupationally exposed populations are not exposed above the exposure limits;
3. Low-cost measures should be taken to prevent exposure to very low frequency electric and magnetic fields in a manner that makes sense without compromising the health benefits, societal benefits, and economic benefits of the electric utility industry;
4. Policy makers, community planners, and manufacturers should be aware of the need to take appropriate measures to prevent exposure to extremely low frequency (ELF) electric and magnetic fields during the construction of new electric utilities and the design of new types of electric equipment (including appliances). Decision makers and community planners and manufacturers should take low-cost measures to prevent exposure to very-low-frequency electric and magnetic fields when building new electric facilities and designing new types of electric equipment, including appliances;
5. Consideration may be given to modifying existing processes to reduce the level of exposure to very-low-frequency EMFs from a facility or equipment if other additional benefits (e.g., increased safety) can be realized or if the additional cost is not required or is very low;
6. When considering modifications to existing sources of very-low-frequency EMF emissions, it is reasonable to consider the following low-frequency EMF emitting sources, a combination of safety, reliability, and economic benefits should be considered;
7. local governments should strengthen netting management, and unintentional ground currents should be reduced and safety ensured when building new electric facilities or making line modifications to existing ones; and prospective measures to guard against violations of netting management regulations or to judge existing netting management problems are costly
8. State regulators should use an effective, interactive and open strategy to engage all property owners to make informed decisions; this strategy should include ways to reduce each owner's own level of exposure;
9. Local governments should improve the planning of VLEMF facilities, and should involve businesses, local governments, and other stakeholders in the siting of large-scale sources of VLEMF emissions. Businesses, local governments, and the public should be well-consulted in the selection of sites for large-scale sources of very-low-frequency EMF emissions;
10. Both governments and businesses should promote research on electromagnetic radiation to reduce scientific uncertainty about the health effects of exposure to very-low-frequency EMFs.