EMF stands for Electromagnetic Fields. There is a full spectrum of EMFs and some come from nature while others are man-made. Natural sources are the sun, firelight, the earth’s DC magnetic field, and some rare naturally occurring radiation. Unnatural man-made sources are mostly pulsating AC electric and magnetic fields from household 60 Hz electricity to wireless radiation from a Wi-Fi router, cell phone, or mobile phone tower. Artificial light from bulbs and screens are another type of EMF in the visible light spectrum.