Ionizing Radiation

Radiation is a form of energy that travels through the environment. Visible light is a type of radiation that we can see. Infrared and radio waves are invisible types of radiation that cannot be detected with our senses, and as we all know, these types of radiation are fairly benign.

Other types of radiation are not so benign since they can strip electrons from the atoms and cause health effects. For this reason, they are called ionizing radiation. High energy particles such as X-rays, gamma rays, and neutrons are different types of ionizing radiation.

There are many sources of ionizing radiation. Some of the sources occur naturally among us in the environment: for example the granite counter top in your kitchen is slightly radioactive. Another source of ionizing radiation is the cosmic rays from outer space. At ground level, the atmosphere shields us from most of it but as you climb in altitude, the cosmic ray levels increase.

Collectively, the ionizing radiation from these and similar sources is called background radiation. Human activities, such as medical x-rays, generating nuclear power, testing nuclear weapons in the ‘60s, and flying at high-altitude, also contribute to our exposure to ionizing radiation.

Excerpt from the Ohio State University information article, "What are the sources of ionizing radiation?" by Audeen W. Fentiman, Brian K. Hajek, Joyce E. Meredith: http://www.ag.ohio-state.edu/~rer/rerhtml/rer_22.html