As is distressingly normal, little or no context is furnished. How often is there a “RADCON” alert, what does it mean, etc. It might be well below the safety level, for the sake of locating leaks of radioactive material well before they can pose a danger to anyone. Part of this might be material that is getting tracked around by globetrotters who have been in Japan.
Then the alert must be coming from the Harlem area.