Table 1. A comparison of the three calculational models: infinite exposure (IE), estimated exposure (EE), and effective biological exposure (EBE). Results are expressed as reduction factors compared to an. infinite exposure of 1.0 at all times of arrival. Time of EE Shielding x Weathering® xX Time = x Repair = EBE arrival, hr 1 2 3 4 6 8 10 12 14 16 18 20 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.83 0.81 0.79 0.78 0.76 0.75 0.73 0.72 0.71 0.71 0.70 0.69 0.95 0.94 0.94 0.93 0.93 0.92 0.91 0.91 0.91 0.90 0.90 0.90 0.59 0.57 0.56 0.54 0.53 0.51 0.50 0.49 0.49 0.48 0.47 0.47 0.84 0.81 0.79 0.79 0.78 0.76 0.76 0.75 0.74 0.73 0.73 0.73 0.50 0.46 0.44 0.43 0.41 0.39 0.38 0.37 0.36 0.35 0.35 0.34 auWeathering" includes the effects of variation from p72 in decay rate of the external exposure rate and the variation in shielding or "ground roughness" effects as fallout weathers into the soil. calculations are based upon an empirical model. OThe effect of integrating for one yr instead of infinite time. 222 The