Before you get dig your hazmat suit out of the back of your closet, you should probably know that the agency doesn't believe the radiation is at a high enough level to cause any kind of damage. They've simply picked up very low levels of iodine-131 in the atmosphere, a radioisotope that ought to decay and stop emitting radiation in about a week. So, that's good I guess. If you're living in the Czech Republic right now, the sky probably isn't going to kill you.
What's a little more disconcerting is that no one seems to know where these radioactive clouds are coming from. The agency insists that it's not spewing out of the Fukushima plants in Japan, even though the radiation from that disaster did spread quite a ways in March. And an official at the Czech State Office for Nuclear Safety says he's absolutely sure that the radiation isn't leaking out of any nuclear power plant or anything else in the Czech Republic. No one has any idea where the source of this stuff is. It'll probably go away on its own, but mystery clouds of radiation aren't really good things to have floating around for no reason, I feel.
Despite the insistence of Czech officials that they're not causing the radiation, it does seem like the Czech nuclear program could be a likely culprit. The Czech Republic currently draws a third of their total electricity from nuclear sources. They've got six nuclear reactors firing all at once--and they'd like to build more soon. The government has plans to double that power output, making the Czech Republic one of the heaviest betters on nuclear power. Surrounding countries are more suspicious of the radioactive stuff, meanwhile. Germany and Switzerland are trying to phase out nuclear power entirely after seeing how it wrecked Japan, and Austria never touched the stuff after Chernobyl. The problem with nuclear energy is that it usually works just fine, but when it goes south, it goes south real hard. Let's hope that these radioisotope clouds are just a freak occurrence and not an indicator that something's afoot with the Czech plants.