Evaluation method of electromagnetic radiation

Electromagnetic radiation is composed of space *** with the transfer of electrical and magnetic energy, and the energy is generated by the movement of charges; for example, is transmitting signals from the radio frequency antenna issued by the mobile charge, 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. As for man-made sources of radiation, they include microwave ovens, radios, television and radio transmitters, and satellite communication devices.

1 General

1.1 These regulations are established to prevent pollution by electromagnetic radiation, protect the environment, safeguard public health, and promote the development of proper practices associated with electromagnetic radiation.

1.2 These regulations apply to all units or individuals, all facilities or equipment within the territory of the Chinese People's Republic*** and the State 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 the 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. 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; 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 Export 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; f is the frequency in the table, the 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 live in a huge microwave oven.