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RADON411

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.

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Open a state's radon figures

Type a state to open its report: its pooled test figures, its counties by EPA zone, and its highest and lowest counties.

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

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