In recent years there has been much discussion and concern about the potential dangers of electromagnetic radiation (EMR), which includes both RF (radio frequency) energy and power frequency (50–60 Hz) electromagnetic fields.
All life on Earth is adapted to survive in environments of weak, natural low-frequency electromagnetic fields (other than Earth's stable geomagnetic field). Natural low-frequency EM fields come from two main sources: the sun and thunderstorm activity.
But over the past 100 years, man-made regions of very high intensity and a very different spectral distribution have changed this natural EM background in ways that are not yet fully understood. You can learn more about Pulsed Electromagnetic Field Therapy by searching online.
It has been known since the early days of radio that RF energy can interfere with most wirelessly powered systems and devices that process extremely low power signals associated with control systems and medical equipment. Due to the very high density of electromagnetic fields, the heating of body tissues leads to injury. These heat-related health hazards are called thermal effects.
The list could be endless, with seemingly harmless AC (alternating current) operating devices for all intentional and unintentional transmitters. Appreciable radiation occurs when the size of the components and the connecting wires reach one-tenth of the wavelength of the operating frequency. Thus the intensity of the field radiated also depends on the power operated by the equipment.
Some tube lights, spark plugs, washing machines, music systems, power amplifiers, computers, elevators, air conditioners, cable TVs, computer screens, etc. all fall into the category of unintentional transmitters, but can be potential sources of electromagnetic radiation.
All radio and TV broadcasting systems, telecommunication systems and equipment, radars, mobile phones, etc. are intentional transmitters of electromagnetic radiations and can result in specific effects on various systems apart from causing serious interference problems and affecting the human body.