"A dirty nuke would not be nearly as bad...apparently more a weapon for fear creation."
It's been over 25 years since I studied radiation physics but this is wrong. It all depends upon the substance and it's half life...I would rather have a small nuke than a dirty bomb using some of the 20 kilos of missing Uranium. The media is spreading this misinformation to quell panic but those of us who have worked with these radioactive isotopes recognize their spin for what it is. A dirty nuke is called dirty for a very good reason...
The media title "dirty bomb" can cover such a wide area of effects as to be almost useless. If you had a sub-critical amount of plutonium, finely divided, you couldn't make a nuke explosion, but you really could do some damage by rendering an area uninhabitable. At the other end, I could take my dentist's x-ray machine, blow it up with a stick of dynamite, and call it a "dirty bomb" (it would raise detectable radiation levels in the vicinity), but it would be ridiculous to cordon off half the city, spend billions on clean-up, etc.
Unless we know what we're talking about, in quantitative terms, any analysis of a generic "dirty bomb" (who has a clean one, anyway) is mostly speculation.