Yes. Children breathe more rapidly and have developing lungs, making them more vulnerable to radon-induced cellular damage. The EPA emphasizes mitigation for homes with children, particularly where they sleep on lower floors.
More detail
Children have roughly 2x the breathing rate of adults per kilogram of body weight, and their lung tissue is in active cellular division throughout childhood. Both factors increase the dose-rate of radon-daughter alpha radiation per unit of indoor exposure. Long-term exposure during childhood appears to carry higher per-unit-exposure cancer risk than equivalent adult exposure, though epidemiological data is harder to isolate. Practical implication for Cincinnati households: if a child sleeps in a basement bedroom or in a finished lower-level family room with extended hours of use, the household-weighted exposure picture is meaningfully worse than for an upper-floor-only sleeping configuration. Mitigation cost-benefit math tilts strongly toward "mitigate" at the borderline 2.0-4.0 pCi/L range when children are present. Cincinnati school context: Ohio law requires public schools to test for radon and address elevated levels in occupied classroom spaces. Private schools and daycares are also encouraged but not always mandated. Parents concerned about exposure during school hours can request the school's most recent radon test result; most Cincinnati districts publish them in their facilities documentation. Home is typically the higher-exposure environment.