Non-ionizing radiation is the term given to radiation in the part of the electromagnetic spectrum where there is insufficient energy to cause ionization. It includes electric and magnetic fields, radio waves, microwaves, infrared, ultraviolet, and visible radiation. NIR is much less energetic than ionizing radiation, which includes gamma or X-rays, which can break molecular bonds and displace (or remove) electrons from atoms or molecules. This means that ionizing radiation directly cause changes in living cells, and so poses a different set of health risks than those posed by NIR, which is less understood.
A measure of the rate of RF (radiofrequency) energy absorbed by the body from a source – such as a cell phone. SAR provides a means for measuring human exposure to RF which is widely used to define recommended or regulated levels of RFR intensity. Intensity here refers to the the degree to which the energy absorbed by the body increases body temperature. SAR is measured as a certain number of watts of energy absorbed per a specified amount of body mass. For example, the U.S. Federal Communications Commission (FCC) enforces a SAR limit of 1.6 watts per kilogram, or 1.6 W/kg.
