I’ve put together a map that shows the average indoor radon level of every county in Iowa. Click on the image above to access the map.
The green color on the map indicates that the county has an average indoor radon level of 3-4 (pCi/L) – a safe level. All the other colors indicate unsafe levels of radon. Yellow is 4-7 (pCi/L), red is 7-9 (pCi/L) and blue is 9-12 (pCi/L). The national average indoor radon level is about 1.3 (pCi/L) according to the Environmental Protection Agency.
Go here for information on the dangers of radon exposure.