According to the energy of photons from high to low, electromagnetic waves can be divided as follows:
1, ionizing radiation, such as X-rays, gamma rays, can ionize gases and molecules, which can cause direct biological
effects such as burns or cancer. Also, particle beams have similar ionizing and biological effects, such as electron beams,
ion beams, and neutron beams. (This is a type of ionizing radiation.)
2, Ultraviolet, visible & infrared light, can cause electronic excitation, but have no ionizing effect.
3, Microwaves and high-frequency radio, which have a heating effect.
4, low-frequency radio and utility power, static field, basically no heating effect.
The latter is electromagnetic radiation as described in general life.
(I) Health Effects of Static (Magnetic) Fields
First of all, it is now certain that short-term exposure to a magnetic field of 1-2 tesla (10,000-20,000 gauss)
is safe. But it is difficult to be experimentally certain that long-term exposure to magnetic fields on the order of millitesla (10 gauss, the Earth's magnetic field strength is around
1 gauss) will not produce any adverse health effects, and so far there is no indication
that there are any such effects, including in adults, children, and pregnant women, and there is no existing theory that suggests that there might be
such effects. p>such an effect. Analyses of health data for medical NMR*** vibration (0.15-4 Tesla) examinees and workers in industrial settings (0.5-300 Tesla
) did not reveal significant deviations from other populations.
Because electric fields are easily shielded by a variety of effects, electrostatic fields have much less of an effect on health than static magnetic fields.
If you use an assistive device such as a cardiac pacemaker, try to avoid exposure to magnetic fields greater than 0.5 tesla (5,000 gauss)
.
(ii) Cell phone radiation
Because wireless communication base stations and broadcast antennas operate at distances far greater than that of a cell phone, in most cases their radiation
has fewer health effects than that of a cell phone.
Microwave and high-frequency radio, if it reaches a certain intensity, can have adverse health effects, including cataracts, burns
and heatstroke, all of which are due to heating effects.
Governments and many international organizations have set standards for safe radiation intensity, which vary in specific numbers
but are generally similar (~0.5mW/cm^2).
In most cases, it is safe to live and work on the top floor of a building where a mobile base station is installed, because the energy radiated downward by either the high-gain or low-gain antennae used for wireless communications is very small, and then the roof and walls usually
absorb 80-90% of the energy, and even more in the case of a reinforced concrete roof. and even more in the case of reinforced concrete roofs. Usually when these antennas are operating at maximum power, the radiation intensity is only exceeded within 8 meters horizontally.
It is possible that some people, such as children or pregnant women, may be more sensitive to radiation, but we have found no evidence of this.
Taking into account that these people may exist, the allowable values in the various standards are generally set at 5-10 times the safe amount.
Radiation within the allowable values won't affect medical devices such as cardiac pacemakers, but don't place your cell phone directly on top of that
device.
There is no evidence that cell phone use causes headaches, mood or behavioral changes, or cancer, even at 20 times the allowable level of radiation.
At energy absorption rates approaching 1W/kg of body weight, it may cause some cellular mutations and miscarriages in pregnant women. Radiation intensities comparable to this
are about tens of times the permissible value.
(iii) High-voltage transmission lines
Epidemiologic studies of residents and workers in special industries near high-voltage lines have found no evidence that electromagnetic fields at utility
frequencies induce cancer. The same results have been obtained in animal tests. There is no theory that low-frequency electromagnetic fields induce cancer
.
Usually, if you are more than 20-70 meters away from a high-voltage line, the electromagnetic field generated is lower than that generated by the utility power in a normal home. For 50Hz alternating current, the recommended living distance is greater than 0.2m/kV, and the working distance is greater than
0.1m/kV, multiplied by five if you use a cardiac booster.
By weak indications the incidence of leukemia in children living near high voltage lines is higher than in the general population.
(d) Common electromagnetic radiation in life also includes microwave ovens, induction cooktops, and radio frequency card machines. These devices have a lot of radiation, but the attenuation is relatively fast, generally half a meter to a meter away from the impact is very small.
Meter belongs to the low voltage frequency, almost no radiation
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