PURPOSE: To improve the safety and accuracy of control, by adjusting the opening of a damper positioned in a local air discharge passage for polluted air, based upon a signal that will be issued when a controllable pollution concentration or more has passed, in a remotely controlled and centralized control apparatus for radioactive polluted air of a nuclear power plant or the like.

CONSTITUTION: Levels where alarm is required or not and levels where ventilation is required or not are memorized in the centralized control apparatus B. When air pollution levels 8e at working sites from continuous dust monitors C are inputted, a central control section 12 inputs a display 12e into a dust concentration display section of a display recording section 13, inputs a signal 12d into a ventilation control section 11 and inputs an alarm signal 12f into an alarm control section 14. Thus, according to a prescribed program, the centralized control apparatus B drives a driving motor 7 of an exhaust fan 5 via a motor control repeating section 9 and a damper control repeating section 10 and adjusts the opening of a damper 3. Then a signal 8f is outputted to an alarm system D. Accordingly, the safety and the accuracy of the control can be improved.