Grade-A scare piece by nuclear physicist Peter Zimmerman in today’s International Herald Tribune:

Essentially all analysts, myself included, played down the possibility of using alpha radiation — fast- moving helium nuclei ejected during the radioactive decay of certain isotopes, such as of polonium 210, the substance that killed [Alexander] Litvinenko — as a source of dirty bombs…

Dirty bombs based on gamma emitters, analysts have learned, can’t kill very many people. Litvinenko’s death tells us that “smoky bombs” based on alpha emitters very well could…

The terrorist’s solution lies in getting very finely divided polonium into the air where people can breathe it. Without giving away any information damaging to national security, I see several fairly simple ways to accomplish this: burn the material, blow it up, dissolve it in a lot of water or pulverize it to a size so small that the particles can float in the air and lodge in the lungs. In the end, the radioactive material will appear like the dust from an explosion, or the smoke from a fire.

Air containing such radioactive debris would appear smoky or dusty, and be dangerous to breathe. A few breaths might easily be enough to sicken a victim, and in some cases to kill. A smoky bomb exploded in a packed arena or on a crowded street could kill dozens or hundreds.

Help me out here. By Zimmerman’s own estimation, the dose that killed Litvinenko was “perhaps the size of a couple of grains of salt.” What he doesn’t mention is that the street value of those grains was a cool $10 mil. Doctors believe that he would have been killed with even 1/10th the dosage, which means we’re talking about $1 million per lethal dose. Do the world’s jihadis have nothing better to do with the Saudis’ money than drop half a billion dollars on a “smoky bomb” that would kill 500 people?

What am I missing?