The last couple days have seen a lot of improvement in access to good radiation information. The U.S. EPA now has a Daily Data Summary website which you should bookmark in case things get hot; today’s 1pm update continues to say that “(EDT) EPA’s RadNet radiation air monitors across the U.S. show typical fluctuations in background radiation levels. The levels detected are far below levels of concern.” In terms of maps, I copied the latest projection for March 21-23 from Austria’s Central Institute for Meteorology and Geodynamics. It only shows local Japan; their global map isn’t updated yet. Also, please be reminded that this is not actual particle data over the ocean, it is a projection based on the weather patterns.

There are a couple informal sites that seem reputable, including a blog from the Weather Underground.