The effect of the aggregation of radiated disturbances from multiple emitters on the limit-setting model for radio protection is studied. The mean value of decibel-scaled interference power with and without aggregation are compared under the condition that the distance from the victim receiver to an emitter is lower-bounded by the protection distance. It is found that there is a critical emitter density beyond which the mean aggregate interference power exceeds the interference power from a single emitter located at a protection distance, which leads to the necessity of reduction (tightening) of a limit. Under low density and high propagation loss conditions, in contrast, the total received power is predominantly affected only by the nearest emitter, i.e., the model approaches to a single-emitter interference model. On the basis of the above results, we discuss how the interference aggregation effect can be introduced into the conventional limit-setting model.