from 8.0 to 40 pCi/L, and above 40 pCi/L

In this range you should conduct a short-term follow-up measurement within the next few weeks, under closed house conditions. A long-term measurement is NOT recommended because exposure at these levels could pose an increased health risk.

If, however, this is a follow-up (confirming) test, it is recommended that you take remedial action to reduce your radon levels.  

A list of Iowa Certified Radon Mitigators can be found at the Iowa Department of Public Health or by clicking here