Everything I've seen so far shows no changes in radiation here in the U.S. In fact, when Chernobyl totally melted down and exploded, scattering the entire contents, changes in the radiation levels here in the
U.S. were barely noticeable. The jet stream is there, for sure, but the radioactive nuclides are not air, they are heavy particles. Heavy levels of radiation could cause elemental transmutation of the particles in and around the reactor, as well as the air around the reactor, which could be carried by the jet-stream. If we see any radiation, it will most likely be later this evening. The EPA is also setting up many more monitors along the west coast as well as Guam, Hawaii, and Alaska. I'm just wary of Fred in his basement with a cold war era Geiger counter who suddenly hears it click "slightly faster than it did last night" and posts on the internet that the Japanese radiation is here.
I've read that one micro-gram of plutonium will (not can) kill a human. And it seems there's plutonium be scattered about all over the place over there. There's not only radiation factor but the contamination factor that could linger on for I dunno how long???
And your skepticism of Fred in his basement summarizes my skepticism that we'd get any form of the truth regarding this mess from government or the MSM.