Is there any radiation from postal facilities?

Electromagnetic radiation (Electromagnetic Emission) is a phenomenon that emits electromagnetic energy from a source, which can be categorized into radiated emission (Radiated Emission) and conducted emission (Conducted Emission), and radiated emission, which is also what we call electromagnetic radiation, refers to " electromagnetic energy propagated through space, useful or unwanted". In general, the main influence on the electromagnetic environment is electromagnetic radiation. Arranging these electromagnetic waves in order of wavelength or frequency is the electromagnetic spectrum. If each band is arranged in order of frequency from lowest to highest, they are industrial frequency electromagnetic waves, radio waves, infrared, visible light, ultraviolet, X-rays and r-rays. Radio has the longest wavelength and cosmic rays have the shortest wavelength. Types of Electromagnetic Radiation Pollution Sources 1 Radio and television transmitting equipment, the main sector for the transmitters and relay stations of radio and television around the world. This is the most serious electromagnetic radiation, because it is generally on kilowatts of high-power transmitting stations. 2 communications radar and navigation transmitting equipment communications, 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 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 electromagnetic radiation equipment: mainly for the electronic gas pedal and a variety of ultrasonic devices, electromagnetic cooker and so on. .4 Transportation system electromagnetic radiation interference, including: electrified railroads, light rail and electrified railways, rail trams, trackless trams, etc.. .5 Electromagnetic radiation from power systems, high-voltage transmission lines including overhead transmission lines and underground cables, substations including power plants and transformer power stations. 6 household appliances electromagnetic radiation, including computers, monitors, televisions, microwave ovens, wireless phones and so on. Then electromagnetic radiation on the human body in fact what harm is caused by people so panic? 1, the mechanism of electromagnetic radiation harm to the human body electromagnetic radiation harm to the human body mechanism is mainly thermal effect, non-thermal effect and cumulative effect. 1 thermal effect: more than 70% of the human body is water, water molecules are subject to electromagnetic radiation friction, causing the body to warm up, thus affecting the normal work of the body organs. Generate thermal effect on the corresponding electromagnetic wave power density in 10mW/cm2; microscopic thermal effect 1 mW - mW/cm2; shallow thermal effect in 10mW/cm2 below. Thermal effect can cause irreversible damage to human tissues or organs, such as: eyes produce cataracts, male infertility: when the power of 1000W microwave direct irradiation of people, can be in a few seconds lead to death.2 non-thermal effect: the organs and tissues of the human body there is a weak electromagnetic field, they are stable and orderly, once the interference of the external electromagnetic field, in the equilibrium state of the weak electromagnetic field is about to be on the human body. Non-thermal effects are reflected in the following aspects: the nervous system: the human body repeatedly subjected to electromagnetic radiation, the central nervous system and other aspects of the function changes. For example, the conditioned reflex activity is suppressed and bradycardia occurs. Sensory system: low-intensity electromagnetic radiation, can make people's olfactory function decline, when the human head by low-frequency low-power acoustic pulse irradiation, will make people hear as if the machine rings, insects or birds chirping sound. Immune system: China has a preliminary observation, long-term exposure to low-intensity microwave people and normal people of the same age compared to its body fluids and cellular immunity indicators in the immunoglobulin 1gG decreased, T-cell wreaths and lymphocyte conversion rate of the product of the decrease, so that the human body's body fluids and cellular immunity decreased. Endocrine system: low-intensity microwave radiation can make the human thalamus - pituitary - adrenal dysfunction; CRT, ACTH activity increases, endocrine function is significantly affected. Genetic effects: microwaves can damage chromosomes. Animal experiments have been found; with 195MHz, 2.45GHz and 96Hz microwave irradiation rats, will be in 4-12% of the spermatogonial cell bone formation of chromosomal defects, rats can inherit such defects, chromosomal defects can be caused by the injured mentally retarded, shortening the average life expectancy. 3 Cumulative effect: thermal and non-thermal effects on the human body, the damage to the human body has not yet had time to repair itself before, again by electromagnetic radiation, the degree of damage will occur cumulatively, and in the long term, will become a permanent disease, life-threatening. For long-term exposure to electromagnetic radiation group, even if the power is very small, very low frequency, may also induce unexpected lesions, cause alarm. In 1998, the World Health Organization's latest survey shows that electromagnetic radiation on the body has five major effects: First, electromagnetic radiation is the main cause of cardiovascular disease, diabetes, cancer mutation. The United States of America, a cancer treatment foundation for some of the electromagnetic radiation damage to a sample of patients, the results show that people working near high-voltage lines 24 times faster. Second, electromagnetic radiation on the human reproductive system, the nervous system and the immune system caused direct harm. Damage to the central nervous system, the head of the long-term impact of electromagnetic radiation, light cause insomnia, headache, dizziness, fatigue, memory loss, irritability, depression and other neurasthenia, heavy cerebral cortex cells weakened activity, and cause brain damage. Third, electromagnetic radiation is caused by pregnant women miscarriage, infertility, teratology and other pathologies triggering factors. Electromagnetic radiation is harmful to the human body in many ways, women and the fetus is particularly vulnerable, the survey showed that: 1 to 3 months for the embryonic period, subject to strong electromagnetic radiation may cause limb defects or deformities; 4 to 5 months for the fetus growth period, subject to electromagnetic radiation can lead to immunity function is low, the birth of the body is weak, poor resistance. Fourth, excessive electromagnetic radiation directly affects children's tissue development, bone development, vision loss; liver hematopoietic function decline, serious can lead to retinal detachment. Injury to the eye power density and the formation of cataracts in the time of the threshold curve is not a straight line, irradiation of the rabbit's eye at each frequency seems to require a microwave power density threshold, below which, even if continuous irradiation does not produce eye damage. Above 500MHz, the minimum power density for cataract formation is about 150 mW/cm2, and the possibility of eye damage caused by frequencies below 500MHz cannot be completely excluded. Fifth, electromagnetic radiation can make men's performance decline, women's internal disorders, menstrual disorders. In 1998, the World Health Organization (WTO) in the latest revision of the computer screen and workers' health problems pointed out that: in the computer screen work environment, some factors may affect the outcome of pregnancy. The first affected is the man, long-term exposure to electromagnetic radiation, may make the male sperm reduction, so that the sperm genetic deformities and may become sterile or teratogen; secondly, pregnant women, it has been reported that in front of the computer for more than 20 hours of work a week pregnant women to give birth to a deformed probability than the average pregnant women 2-3 times higher than the probability of giving birth to a girl. Although there is now equality between men and women, it would be a disaster if the ratio of men to women is out of proportion. The following is a specific explanation of electromagnetic radiation related to communication equipment: when people use cell phones, the cell phone will transmit radio waves to the transmitting base station, and the base station will also transmit radio waves to the cell phone. Cell phone antenna and receiver close to the ear, the antenna from the head is only 2 ~ 5cm, the head is in the near-field radiation area of the cell phone, the electromagnetic radiation is relatively large; and the general public cell phone base station from the public activity area is about 15 meters to 50 meters, in terms of its radiation field in the people, belongs to the far-field radiation range, and the role of electromagnetic radiation on the human body as a whole or a full range of dispersion. The farther away from the antenna, the smaller the intensity of electromagnetic radiation, in an ideal situation, the intensity of electromagnetic radiation at a certain point (expressed as power density) and the point to the antenna of the square of the distance inversely proportional to the square of the antenna, i.e.: in the distance from the antenna 1 centimeter at the intensity of electromagnetic radiation than in the 10 centimeters at the intensity of the 100 times greater. Assuming that an ordinary cell phone has a power of 1 watt and is talking at a distance of 10 centimeters from the head, the intensity of electromagnetic radiation received at that point is theoretically equivalent to the intensity of electromagnetic radiation at a power of up to 10,000 watts at a distance of 10 meters from the base station. In fact, most of the public cell phone base stations have a radiated power of less than 20 watts. In this case, the EMF intensity of a public cell phone base station is less than one-fifth of that of a cell phone, i.e., negligible. 　Mobile phone and public cell phone base station electromagnetic radiation intensity measured results are also more consistent with the above theoretical analysis. In the distance from the cell phone base station antenna 10 meters away, the radiation intensity is relatively small, are in the 10μW/cm2 below, while the distance from the cell phone antenna 5 cm radiation intensity is almost in the 50mW/cm2 above. In fact, the base station's transmit power depends on the cell phone and base station communication distance and the number of users, the existing GSM, CDMA system are using micro-cellular coverage, set up thousands of low-power base station, the base station's transmit power to reduce the intensity of electromagnetic radiation is also correspondingly weakened. At present, the public mobile communication network is very mature, some of the cell base station coverage radius is only a few tens of meters; at the same time, this kind of micro-cellular base station coverage system reduces the intensity of electromagnetic radiation of the cell phone, because today's GSM, CDMA, PHS and other cell phones, have power adjustment function, the better the cell phone searches for signals, the closer the distance to the base station, the smaller its transmit power. Base station density and radiation intensity of the relationship between cell phone holders in the "mobile" process can be connected to the phone at any time, and to maintain a clear, stable call effect, because the phone and the base station and the base station controller, with the help of wireless channels, the transmission of communication information, control signals, test signals. In order to ensure the call quality, cell phones and base stations automatically follow the computer control program agreed by both sides, dynamically adjusting the call channel, electromagnetic radiation power and reception sensitivity, while also realizing the intelligent registration of international and domestic roaming, switching between the local area and the base station, and recording the length of the call and the cost of a variety of functions. According to the above control principle, a coverage radius of 500 meters to 700 meters of BTS base stations within the cell phone is farther from the base station, corresponding to the channel and the cell phone's peak power of the transmission is stronger. Tests show that: when the GSM cell phone from the base station 700 meters from the building to talk, the base station corresponds to the channel of the transmitter power of about 13W, GSM cell phone transmitter peak power of about 2W; when the phone to move to the base station from 1 meters to 200 meters away, the base station and GSM cell phone corresponds to the channel transmitter power will be automatically adjusted in about 0.1W. Therefore, the higher the density of mobile communication base stations, the lower the intensity of electromagnetic radiation from each base station; the closer the GSM cell phone is to the mobile communication base station, the lower the amount of electromagnetic radiation from the GSM cell phone to the caller in the process of using the GSM cell phone). Of course, this explanation only explains the cell phone to the user's radiation, according to this theory, standing on the base station radiation is the smallest, wrong! Because the base station itself on the people still have radiation, so if your home is living near the base station, it would be miserable! Indoor electromagnetic radiation protection for the indoor environment of office equipment, household appliances and cell phones electromagnetic radiation hazards, people should take the following protective measures: ● consciously comply with national standards, the correct use of computers, cell phones, microwave ovens and other office equipment and household appliances. ● Electrical appliances should not be placed too centrally. In the bedroom, put as few or even no electrical appliances as possible. ● Do not use electrical appliances for too long, and try to avoid using multiple electrical appliances at the same time. ● Be aware of the distance between people and electrical appliances, and keep them as far away as possible. ● Minimize the use of electric shavers and hair dryers. ● When sitting in front of a computer for a long period of time, it is best to wear protective equipment such as radiation-proof coats, vests, and aprons. At the video display terminal, install a fluorescent screen protection net. ● Drink tea or take spirulina tablets regularly to strengthen the body's ability to resist electromagnetic radiation. ● For household appliances that emit large amounts of radiation, such as electric mattresses, microwave ovens, and electromagnetic stoves, stainless steel fiber cloth can be used to make a cover, or chemical coating can be applied to reflect and absorb the blocked electromagnetic radiation. ● Use your cell phone correctly. At the moment when a cell phone is turned on, the amount of electromagnetic radiation released is the largest, instantly up to 2000mGs (milligauss). It has been reported that a field strength of 10-150 mGs can cause the gene R53, which inhibits cancer, to become diseased, thereby increasing the chance of cancer. The intensity of electromagnetic radiation can be reduced by half after the cell phone is turned on for tens of seconds. Therefore, it is best to answer the phone after the cell phone is connected for a few seconds. When answering the phone, try to keep your head away from the cell phone, or use a separate headset and microphone to answer the call. At the same time, try to minimize the duration of the call, and it is best to take turns listening to the left and right ears. Usually do not hang an open cell phone on your chest to prevent heart damage. Especially for women, electromagnetic radiation has a more significant effect on endocrine and pregnant women.