The progress and application of electromagnetic technology have created a great material civilization for human society, and at the same time brought human beings into artificial electromagnetic fields. Such as household appliances, office equipment, radio and television towers, urban transportation systems, etc. It can be said that in modern society, electromagnetic fields are everywhere.
Scientific research shows that not all electromagnetic fields will have an impact on the ecological environment, and only when the energy exceeds a certain limit will it have a negative impact.
In China and most countries in the world, the power frequency is 50 Hz (some countries use 60 Hz, such as the United States). In the field of electric power or power, the frequency of 50 Hz (or 60 Hz) is usually called the working frequency of power supply (power frequency for short).
The existing forms of low-frequency electric field, magnetic field and high-frequency electromagnetic field, as well as their action mechanism and biological effect on organisms are completely different.
The power frequency of China is 50 Hz, which belongs to extremely low frequency. The official document of WHO points out: "The only practical way for extremely low frequency fields to interact with biological tissues is to induce electric fields and currents in biological tissues. However, at the exposure level of extremely low frequency field, the induced current is lower than the current naturally existing in our body. "