Bands show each emergency action level as the dose a person would accumulate over a 40-hour exposure window: UE 1 mrem, Alert 10 mrem, SAE 100 mrem, GE 1 rem TEDE. (Live RadNet readings are dose-equivalent rates in mrem/h; normal background runs ~0.003–0.013 mrem/h, roughly 0.1–0.5 mrem accumulated over 40 hours.) Real EALs are evaluated at the plant site boundary; this scale is a public reference frame, not a measurement at the fence. Every RadNet reading on this map sits in the green zone.
About this map. RadNet monitors measure regional environmental background radiation, not radioactive material released from a nuclear plant. EPA sites them at city centroids for population coverage, so the nearest monitor to a given plant can be tens of miles away, and its reading is dominated by natural background, radon, and rainfall. The 10 and 50-mile rings are nominal Emergency Planning Zones; actual EPZ boundaries follow terrain, roads, and jurisdictions. This map is for context and education, not an emergency resource. In an actual event, follow your local emergency officials and the NRC.