The Electromagnetic Spectrum
Radiation exists all around us, from both natural and manmade sources, and is in two forms: ionizing and non-ionizing radiation.
Ionizing radiation is a form of energy that acts by removing electrons from atoms and molecules of materials that include air, water, and living tissue. Ionizing radiation can travel unseen and pass through these materials.
What is non-ionizing radiation?
Non-ionizing radiation exists all around us from many sources. It is to the left of ionizing radiation on the electromagnetic spectrum in the figure below.
- Radiofrequency (RF) radiation used in many broadcast and communications applications
- Microwaves used in the home kitchen
- Infrared radiation used in heat lamps
- Ultraviolet (UV) radiation from the sun and tanning beds
The dividing line between ionizing and non-ionizing radiation occurs in the ultraviolet part of the electromagnetic spectrum [shown in the illustration of the electromagnetic spectrum above]. Radiation in the ultraviolet band and at lower energies (to the left of ultraviolet) is called non-ionizing radiation, while at the higher energies to the right of the ultraviolet band is called ionizing radiation.
As we move to the left of the visible light band in the figure above, we move to lower frequencies. By “frequency” we mean how rapidly these waves move up and down. The lower the frequency, the lower the energy.
In these lower frequencies on the left side of the electromagnetic spectrum, we find infrared, microwave, radiowaves, and cell phone range radiation.