The number of studies on the effects of electromagnetic radiation on human health ranges in the hundreds.

Although there have been a wide range of results, there is enough evidence to show a cause for concern regarding people's health who have continuous or prolonged exposure to electromagnetic frequencies. Electromagnetic radiation is a field of energy that is created around electrical and battery operated devices such as electric clock radios and cell phones that can have an effect on human health. Over one hundred of them have been published by 1990 and since then many more have been conducted. Most of the EMF exposure comes from man made sources, including house wiring, electrical appliances, overhead power lines, airport and military radar, vacuum cleaners, electric water ionizers, infrared saunas, clock radios, substations, transformers, hair dryers, refrigerators, freezers, washing machines, clothes dryers, old style televisions, computers, cordless phones, cell/mobile phones, wi fi modems and neighbourhood electrical boxes. Natural sources come from events such as thunderstorms, even the earth's magnetic field gives off electromagnetic frequencies.

There are many sources of electromagnetic radiation, some of them natural but most of them man made.