Data
Radon411 data
Every number here comes from a named public agency. Explore it county by county, see what each term means, and see how much of the country it covers.
What it is
What Radon411's data is
Radon411 brings together public radon data for every U.S. state and county and keeps three kinds of number apart. Predicted figures are a forecast for an area: EPA assigns every county to one of three radon zones, and USGS classifies geology into low, moderate and high radon potential. Measured figures come from radon tests that were carried out and reported to a public health agency: CDC's testing statistics, and the results a state publishes itself. Calculated figures are worked out by Radon411 from those, always labelled as calculated, with the method set out on the methodology page.
None of them is a reading of a home. A zone is a prediction for a whole county, and a share of tests describes the tests reported for an area, not every home in it. EPA says the zone map is not meant to decide whether a home should be tested, that homes with elevated levels have been found in all three zones, and that every home should be tested. Only a test tells you the radon level in one home.
Coverage
How much of the country the data covers today
- 56
- States and territories, from Census boundaries
- 3,231
- Counties and county-equivalent areas, each with its own report
- 3,138
- Counties with an EPA zone, of 3,231
- 2,863
- Counties with CDC testing data, of 3,231
Four ways in
Explore the data
- Data explorerEvery U.S. county, one row each. Filter by state, EPA zone, USGS potential and testing data; sort and page through it; every view is a link.
- Data dictionaryWhat every term and column means, in plain words and technically.
- SourcesEvery source behind the numbers and the guides, by name, grouped by what it feeds, with a date for each.
- MethodologyWhat Predicted, Measured and Calculated mean, how each calculated figure is worked out, and how often the data is refreshed.
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Where to go from here
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