What are the common sources of electromagnetic radiation?

The common types of electromagnetic radiation sources in life mainly include the following 1. radio and television transmitting equipment, mainly for the transmitter and relay stations of radio and television broadcasting everywhere.　　2. communications radar and navigation communications transmission equipment, including short-wave transmitters, microwave communication stations, terrestrial satellite communication stations, mobile communication stations.　　3. industrial, scientific research, medical high-frequency equipment. This type of equipment to convert electrical energy into heat or other energy to be utilized, but accompanied by electromagnetic radiation generated and leaked out, causing environmental pollution in the workplace. Industrial electromagnetic radiation equipment: mainly for the high-frequency furnace, plastic heating machine, high-frequency medium heating machine. Medical electromagnetic radiation equipment: mainly for high-frequency physiotherapy machine, ultra-short-wave physiotherapy machine, ultraviolet radiation physiotherapy machine. Scientific research with electromagnetic radiation equipment: mainly for electronic gas pedal and various ultrasonic devices, electromagnetic cooker.　　4. electromagnetic radiation equipment for transportation system, including: electrified railroad, light rail and electrified railway, tram, trolley bus and so on.　　5. electromagnetic radiation equipment for electric power system, including high-voltage transmission lines, overhead transmission lines and underground cables, and substations, including power plants and transformer power stations.　　6. Household appliances electromagnetic radiation equipment, including computers, monitors, televisions, microwave ovens, wireless telephones, etc..　　Appropriate use of electromagnetic fields, conducive to human health The Earth is a large electromagnetic field, people must be compatible with the Earth's magnetic field to survive. From a certain point of view, the electromagnetic field is essential. If a person lives in a space without an electromagnetic environment, it will certainly cause disorders in body functions. Therefore, the presence of an appropriate amount of electromagnetic environment is beneficial to human health.　　Since human life activities contain a series of bioelectric activities, these bioelectrics are very sensitive to the electromagnetic waves of the environment. Therefore, human beings have made many beneficial instruments and devices utilizing the subtle relationship between electromagnetic waves and the human body. When electromagnetic radiation is applied to a part of the human body in an appropriate manner and time, it can treat a variety of diseases. Electromagnetic waves, especially microwave waves in the most widely used in clinical applications, the use of microwave can be treated frozen shoulder, chronic osteomyelitis, coronary heart disease and so on.　　Radiation accumulation, the body will have an accident Under normal circumstances, the human body can adapt to the earth's electromagnetic field. However, when the human body is exposed to a certain dose and a certain period of time after the electromagnetic radiation, will be subject to different degrees of harm. The mechanisms by which electromagnetic radiation harms the human body are mainly thermal, non-thermal and cumulative effects. When the human body receives electromagnetic radiation, the molecules in the body with the conversion of electromagnetic field rapid movement, so that the human body warming, thermal effect will cause central nervous system and plant nervous system dysfunction, mainly manifested as dizziness, insomnia, forgetfulness and other sub-health manifestations. Non-thermal effect that absorption of radiation is not enough to cause an increase in body temperature, but also cause physiological changes and reactions. Living and working in this environment for too long will result in symptoms such as dizziness, fatigue and weakness, memory loss and loss of appetite. Cumulative effect refers to the thermal and non-thermal effects on the human body, the human body has not yet had time to repair itself before the injury, again subjected to electromagnetic radiation, the extent of its damage will occur cumulatively, and over time it will become a permanent pathology, life-threatening.　　Excessive electromagnetic radiation can lead to infertility, mental retardation and blood diseases, etc. Excessive electromagnetic radiation can cause damage to a number of systems and organs of the human body, mainly manifested as follows: 1. Neurological system: neurasthenia and vegetative nervous system dysfunction symptoms, manifested as dizziness, headache, insomnia, sleeplessness, fatigue, memory loss, emaciation, mood and neurological dysfunction.　　2. Reproductive system: manifested as reduced sperm count and quality in men; menstrual disorders in women, increased chances of miscarriage in pregnant women, malformation of fetus, and may lead to mental disability in children.　　3. Cardiovascular system: manifested as palpitations, chest tightness, bradycardia, decreased blood volume of heart beat, sinus arrhythmia, etc.. If patients with pacemakers are exposed to high-voltage electromagnetic radiation, it will affect the normal use of pacemakers.　　4. Immune system: Reduced immune function may occur. The peripheral blood leukocytes, especially lymphocytes, are reduced, the ratio is abnormal, and the phagocytosis ability of leukocytes is reduced.　　5. Visual system: Eyes are one of the more sensitive organs to electromagnetic radiation and are easily damaged by electromagnetic radiation. Long-term exposure to low-intensity electromagnetic radiation can lead to visual fatigue, eye discomfort and eye dryness. Excessive electromagnetic radiation can lead to vision loss, and in severe cases can lead to retinal detachment. The eye is not covered by fat layer, the eye tissue contains a lot of water, the lens lacks blood vessels to dissipate heat, in the thermal effect of electromagnetic radiation, the lens protein coagulation and enzyme metabolism disorders, resulting in clouding of the lens, serious cataracts will be formed. At the same time, strong electromagnetic radiation will make the cornea hurt, resulting in visual fatigue, vision loss or even loss.　　It is worth noting that different people or the same person at different ages on the ability to withstand electromagnetic radiation is not the same, the elderly, children, pregnant women belong to the sensitive population of electromagnetic radiation.