Department of
Environmental Quality

There are several types of radiation, including:

• Electromagnetic waves, which include gamma rays, X-rays, ultraviolet, visible light, infrared, and radio waves

• Emitted particles, such as alpha particles, beta particles and neutrons

Radiation loses energy as it passes through “matter” including the “matter” that makes up the human body. For example, sunburn is the result of overexposure to ultraviolet radiation. To minimize the effects of this type of radiation, exposure to the sun should be kept low and the body shielded by clothing and sunscreen.

Comparison of Alpha, Beta, and Gamma Radiation

How easily are three common types of radiation (alpha, beta, gamma) stopped? The graphic below shows that alpha radiation is stopped by a sheet of paper, wood stops beta particles, but lead or concrete are required to stop gamma rays.

Radiation Dose

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.