Has affected millions of peoples health already and whole ecosystems. And the consequences will cumulate from this thousands of years. Count that in your equation and get more informative numbers.
The dispersed fallout? Hard to quantify because of it's dispersedness and long term slowness. But it is for example plutonium and we know it's effects on life on Earth, so one could proceed from there with some math and futurological trend extrapolation. And simply by using the knowledge we have about plutonium mixed with common sense.