The strength of electromagnetic radiation and national standards
According to the concept of electromagnetic radiation, electromagnetic radiation is actually a type of energy, and its impact on the environment mainly depends on the strength of the energy. The dimensional units of its intensity mainly include power density, electric field strength, and magnetic induction strength
Power density: refers to the high-frequency electromagnetic energy received or emitted per unit time and unit area, measured in watts per square meter (W/m2). When evaluating high-frequency electromagnetic radiation environments, power density is commonly expressed in microwatts per square centimeter (μ W/cm2).
Magnetic induction intensity: represents the magnetic flux per unit volume or area, used to describe the strength of the energy of a magnetic field, measured in Tesla or Gauss (T or Gs).
The biological effects caused by electromagnetic radiation energy are related to the intensity of electromagnetic radiation, irradiation time, frequency of radiation waves, and physical length of exposure of organisms.
In order to control the pollution of electromagnetic waves on the environment, protect people's health, and promote the development of electromagnetic technology, China has formulated the "National Standard for Environmental Electromagnetic Wave Health Standards of the People's Republic of China" and "GB9175-88". Usually, electric field strength V/m and power density μ W/cm2 are used as units.
The Chinese government has always attached great importance to public safety and has issued the "Regulations on Electromagnetic Radiation Protection" (GB8702-88). The electromagnetic radiation limit standard specified in this regulation is much stricter than international standards (see Table 1, usually used in the RF segment), and the standard limit is set at 40 μ W/cm2.
Internationally, the radiation limit standard for the power frequency range (i.e. frequency 50Hz) is usually set at 0.4 micro Tesla (μ T).
From Table 1, it can be seen that the public radiation limit standard in China is only 40 μ W/cm2, which is more than 10 times stricter than the International Committee on Non Ionizing Radiation and EU national standards, and 5 times stricter than the Australian standard.
