Mobile telephone systems, radio broadcasters and other communication systems are the main sources of radiation in this area. In most cases measurements are taken under far field conditions and so use of an E field probe will be sufficient. In the case of low frequency transmitters, we might find near field conditions, and so the H (magnetic) field will also have to be measured.
Workers’ exposure to electromagnetic fields must be monitored for their safety in a wide range of industrial areas, machinery and manufacturing processes. Some examples include induction heating, welding systems and processes, radio frequency (RF) heating, tempering and drying equipment, chemical processes (electrolysis), etc. Home appliances also generate electromagnetic fields that must be measured and evaluated before they can be put on the market.
Low frequency electromagnetic fields are associated mainly with the supply of electricity, through the generation, distribution and use of alternating current (AC), and they are always present in our surroundings. Electricity operates at the frequency of 50 Hz or 60 Hz, depending on the country. Electric power stations, high- and medium-voltage lines, transformers, electric motors and railway lines are the main sources of these electromagnetic fields.
Electricity is very important in the rail industry, since it allows trains to move quickly, quietly, comfortably and with little pollution. High-power and low-frequency energy is used for moving trains and radio frequencies (RF) are used for communication. People’s exposure to electromagnetic fields both inside and outside trains, near communication systems and in stations must be controlled.
Magnetic resonance equipment, diathermy and hyperthermia equipment, and electrosurgery equipment are the main sources of electromagnetic radiation in the medical industry. The medical staff using that equipment or working in nearby spaces are exposed more intensely than patients or people who are passing through, and so exposure within the radius of influence of that equipment must be evaluated and controlled. This includes measurements at low and high frequencies using the suitable devices and probes with isotropic response and RMS. The applicable standard is IEC 60601.