I have 2 questions. Hello, George
In addition to what Larainne and others have written, I want to emphasize some things in response to a premise at your original inquiry
Macon, NC where according to the EPA the radon levels are between 2.0-3.9%pCi — George
1) The units of concentration of radioactive material per volume, picoCuries per liter (here, of radon in air) are admittedly an unfamiliar thing to most. Although the abbreviation "pCi/L" does bear a little similarity to "pct." or "percent", it actually has nothing to do with percentages. Unfortunately, this can be a source of confusion. The numbers on the EPA Zone maps are
not percentages.
2) Another important thing to understand is that the EPA Zone Map does
not say that radon
levels are within certain ranges, only that--based on the preliminary information available at the time the maps were constructed (nearly three decades ago)--the predicted
countywide average screening level in the lowest livable area of the building was expected to be in the given range. Therefore, it must be recognized that radon levels in specific buildings in Macon, NC may be less than 2.0 pCi/L or they may be greater, even in some cases much greater, than 4.0 pCi/L.
3) As Larainne said, the radon maps have emphasized, from the start, that they were
not to be used to decide
whether to test. Their purpose was only to help decision-makers allocate limited resources in a manner likelier to have more benefit.
4) Also, from the start, EPA clearly recognized the preliminary nature of the maps and encouraged the development of better information over time.