2015-08-21
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Intensity of electromagnetic radiation is measured in W/m2 and determined by frequency.
Low frequency (0-300 kHz; 1-1000 km) radiated by all electro-devices, cables, cords, power lines.
Center frequency (0.3-3 MHz; 100 m-1 km) – wireless connection (radio).
High frequency (3-30 MHz; 10 m-100 m) – radio.
Very high frequency (30-300 MHz; 1 m-10 m) – TV, radio.
Ultrahigh frequency (0.3-3 GHz; 10 cm-100 cm) – radio.
Superhigh (microwave) frequency (3-30 GHz; 1 cm-10 cm) – radiolocation, satellite communication.
Extremely high frequency (30-300 GHz; 1 mm-10 mm) – radars.
Optical diapason:
- infrared radiation (0.1 mm – 0.76 microns): body with T>0;
- visible radiation (0.76 microns – 0.4 microns);
- ultraviolet radiation (0.4 microns – 0.2 microns): sun, daylight lamps;
- ionizing: radiation.
Biological effect is determined by force, intensity, size of exposed surface, frequency as the higher frequency radiation penetrates deeper.
EMF polarizes body cells (water cells) forcing them to move in EMF frequency. Exposure to EMF also causes ion-currents. Due to mentioned effects EMF causes heating of the body. The heat absorbed by the body from EMF may be backed away to some limit (10 mW/m2), or else it rises the temperature of the body. It has the most adverse effect on organs that much water and poor blood circulation, such as eyes, brain, kidneys, stomach, bladder. Blood circulation system may be imagined as cooling one. Exposure of eyes causes clouding of the crystalline lens, cataract, what appears after several days.
Ultraviolet radiation has the slight ionizing effect yet. They are divided into three subgroups: UVA near the natural, UVB carcinogenic, UVC ionizing (shortest waves, highest frequency). Among effects mentioned above malignant skin and eyes effect. Safe distance to daylight lamp: 3 m, to welding work: 5 m.
