The EPA says children have been reported to face greater risk than adults from some radiation-related cancers, but there are no conclusive data showing greater risk from radon. Because risk builds over years, a child's long future in the house is the practical reason to act.
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The honest version matters here. Radon risk is driven by concentration and time, and children who grow up in a house spend many years in it. A basement playroom, a teenager's lower-level bedroom, or a finished rec room in a Westerville or Gahanna split-level puts young people where readings are usually highest. The EPA also advises retesting on a lower level whenever a household starts using it regularly. Schools are a separate track; the Ohio Department of Health publishes a radon-in-schools FAQ, and parents can ask a district about its testing. At home the steps are the same for every family: test the lowest level that is lived in, fix results of 4 pCi/L or more, and consider fixing between 2 and 4. See finishing a basement safely.