Why is the public afraid of electromagnetic radiation? There is a misunderstanding here
Will the electromagnetic radiation from mobile phones and base stations harm human health? The public is very concerned about this, and domestic media is filled with various expert suggestions. In fact, developed countries and international organizations have conducted years of research on this topic, and the conclusion is that the electromagnetic radiation from mobile phones and base stations is not related to diseases such as brain tumors and leukemia. The electromagnetic radiation in daily life is not harmful to human health, which is a consensus in the scientific community.
Why is the public afraid of electromagnetic radiation? There are two main misconceptions: firstly, the difference between ionizing radiation and electromagnetic radiation is confused. High intensity ionizing radiation such as X-rays can indeed break the chemical bonds of human tissues, causing harm to the human body, while the intensity of electromagnetic radiation is very low and does not cause the same harm; The second concern is about the non thermal effects of electromagnetic radiation. Electromagnetic radiation does indeed have thermal effects, and the electromagnetic furnace utilizes thermal effects, but rigorous scientific experiments do not support the non thermal effects of electromagnetic radiation.
The World Health Organization and other international authoritative institutions only recognize the potential hazards of electromagnetic radiation thermal effects. Various countries and international organizations have established limit standards for public electromagnetic radiation. Although the specific values are not the same, the measurement methods and numerical units are unified. There are two universal measurement standards, namely power density standard and specific absorption rate standard.
1. Power density standard
Power density refers to the radiation power received per unit area, which measures signal strength and can be represented by electric field strength and magnetic field strength, but power density is more commonly used. The following figure shows the regulations on public exposure limits in the current national standard "Electromagnetic Environment Control Limits" (GB8702-2014) in China. The frequencies of mobile phones and base stations fall within the range of 30MHz to 30000MHz.
2. Specific absorption rate standard
The definition of Specific Absorption Rate (SAR) is the differential value of the energy absorbed by a mass element within a given density volume element over time, that is, the electromagnetic energy absorbed per unit time and per unit mass of the organism, expressed in W/kg.
Compared with the power density standard, the absorption ratio takes into account more human conditions and should be a more valuable reference standard. However, it is difficult to operate and requires a human body model to cooperate with. The subsequent algorithms are also very complex. The verification of the power density standard is very simple, and can be measured with a field strength meter or spectrum analyzer,
3. Changes in the new national standard
The name of the new national standard is "Electromagnetic Environment Control Limits", which is different from the replaced old national standard "Electromagnetic Radiation Protection Regulations". The term "protection regulations", which strongly protects human health, has been removed and replaced with "control limits". In recent decades, medical research on electromagnetic radiation has generally not supported the correlation between electromagnetic radiation and its impact on human health. It is believed that deliberate protection is not necessary, and the change in the name of the new national standard has weakened the meaning of protecting human health.
