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10 October 2008

Answer to Question #689 Submitted to "Ask the Experts"

Category: Environmental and Background Radiation — General

The following question was answered by an expert in the appropriate field:

Is there any place where I can obtain background radiation readings for the various states? Will it be possible to determine when these readings were taken and by whom?

Most information on background radiation levels in a particular state is available from the state government, most often via the state Health Department or Environmental Protection Agency (in some states this may be called the Department of Environmental Conservation or Department of Environmental Quality). A very good general summary of natural sources of radiation exposure is found on the Idaho State University Web site. This site also has links to other documents that you might find interesting. Information on background radiation (natural and man-made) can be found on the Nuclear Regulatory Commission Web site. The biggest factors affecting your exposure to natural background radiation are:

Elevation—at higher elevations, you will receive a higher dose from cosmic radiation because there is less atmosphere above you, acting as a shield against cosmic rays.
Local geology—many rock formations, including those with lots of granites, black shales, or coal, will have elevated levels of radiation from uranium, thorium, and/or potassium in the rock. In general, areas with elevated uranium and thorium concentrations in the rock will also have elevated radon levels.

In general, people in the mountain states (particularly in the Rocky Mountains) will have higher exposure to natural radiation because of their elevation and the higher concentrations of granites in these mountains. However, studies have been done that indicate that these radiation levels have no ill effects on the health of residents.

Andrew Karam, CHP
Radiation Safety Officer

Answer posted on 16 February 2001. The information and material posted on this Web site is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Web site. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.