In the process of prison management, the most important job is to prevent prisoners from contacting the outside world, so most prisons and detention centers will install mobile phone blockers. The working principle of the wifi jammer is to shield the host to emit electromagnetic waves with the same frequency as the mobile phone communication signal. In turn, the mobile phone cannot identify the interfering electromagnetic waves and the useful electromagnetic waves. Therefore, it is said that when the mobile phone isolator is working, it radiates electromagnetic waves outward.
Are electromagnetic waves harmful to the human body? Electromagnetic waves have a wide spectrum, and light waves are electromagnetic waves. Some electromagnetic waves are harmful and some are harmless. For example, light waves in electromagnetic waves, it is difficult for humans to survive without sunlight, but excessive sunlight exposure can also cause harm to the human body. Therefore, electromagnetic waves have two effects on the human body: one is thermal effect and the other is biological effect.
For these two kinds of effects, various countries have formulated two electromagnetic wave protection standards, "Electromagnetic Radiation Protection Regulations" and "People's Republic of China Environmental Radio Wave Hygiene Standards". These two standards stipulate in great detail the definition, calculation method, and safety value of the effect of electromagnetic waves on the human body. In fact, all radio communication equipment relies on electromagnetic waves for transmission, such as televisions, radios, radar, radio, sunlight, cosmic rays, lightning, etc., all rely on electromagnetic waves for transmission. We live under the irradiation of electromagnetic waves all the time. It's okay because these exposure doses are lower than the two electromagnetic wave protection standards.