There are several types of radiation, including the following:

• Electromagnetic waves, which includes gamma rays, X-rays, ultraviolet, visible light, infrared, and radio waves
• Emitted particles, such as alpha particles, beta particles, and neutrons

Of interest to many of us is the fact that radiation loses energy as it passes through "matter," including the "matter" that makes up our bodies. For example, sunburn is the result of overexposure to ultraviolet radiation. To minimize the effects of radiation, we usually want to keep our exposure low.

A measure of how energy is deposited by a given source of radiation is expressed by radiation dose. The average radiation dose for members of the U.S. public from natural background is 360 millirem per year.

Do you know your radiation dose? Unlike getting your cholesterol levels tested, there is no simple test to determine your radiation dose, but you can estimate your dose using Oversight's dose calculator.

You can read more about radiation by following these links:

• What are the most common radionuclides and how do they affect my health? (U.S. EPA Web site)
• Understanding Radiation in Our World (pdf 643 kb, 100 pages)
• Understanding Radiation in Our World: Supplement for Journalists                  (pdf 70 kb, 16 pages)