In the unlikely event of a nuclear accident at the nuclear power stations at Daya Bay with radiological release, radioactive materials affect us through different exposure pathways, the significance of which changes with time. For instance, direct external exposure to the radioactive plume first affects us although it is transient. On the other hand, radioactive materials enter the foodchain after several hours or perhaps several days. Only then the ingestion pathway becomes significant. Therefore, time after the nuclear accident determines the order of priority in implementing different phases, namely early, intermediate and late phases, of emergency radiation monitoring.