Radon Test Levels - Test Results
Derivation
Radon test results are shown in picocuries per liter (pCi/L). Test results are evaluated following EPA guidelines of 0 to less than 2; 2 to less than 4; and 4 or more pCi/L.
Standard
The U.S. Surgeon General and the Environmental Protection Agency (EPA) provide the following guidelines:
- Radon test results of 4.0 pCi/L or greater, action should be taken to reduce radon exposure.
Information
We acquired radon test results from private testing laboratories that included tests from 1989-October 31 of the most recent year for available data.
Caveats
We did not assess the quality, accuracy, or precision of individual test results within or between test kit providers or locations. We assumed that test kit use instructions were followed and that information provided by users, such as test duration and test location, was accurate. We do not know if tests were conducted pre- or post-mitigation. Radon test results are not from a representative sample within an area but reflect a convenience sample based on self-selection.
Citation
Washington Tracking Network, Washington State Department of Health. Web. "Elevated Radon Test Results". Data obtained from private testing companies. Published: June 2019.
Geology available as a selectable map layer:
Derivation
The map shows the potential to be exposed to radon based on characteristics of the surface geology:
- High, geology contains uranium or has rock types known to contain uranium.
- Medium (variable), geology may have uranium-containing rock deposited from glacial or other events.
- Low, geology or soil type unlikely to contain uranium.
Reduce the transparency slider to view the geology risk map more clearly.
Large flood deposits from the Missoula Floods occurred periodically 13,000-15,000 years ago. Floods swept uranium-rich rocks from the north and east into the Columbia River basin. Areas, where such rocks were deposited, have elevated radon potential, even though the underlying geology is of low radon risk.
Classifications were derived from the U. S. Geologic Survey (USGS). USGS denotes five categories. We combined the three higher radon risk geologic categories into one “high” classification.
Information
The Division of Geology and Earth Resources at the Washington State Department of Natural Resources evaluated surface geology based on standards established by USGS. Approximately 57,000 uniquely identifiable rock and soil areas were classified into the high, variable, or low risk of producing radon gas. The fine-scale geology map of Washington used in this analysis is 1:100,000.
Caveats
In Washington State, rocks or soil that contain uranium and its product, radon gas, can be anywhere in the state. We classified various risk areas but there is no area with no risk at all.
Citation
Washington Tracking Network, Washington State Department of Health. Web. "Geologic Risk Areas". Data obtained from the Division of Geology and Earth Resources, Department of Natural Resources. Published: 27 December 2018.