(Reuters) – Low concentrations of radioactive particles are heading eastwards from Japan’s disaster-hit nuclear power plant and are expected to reach North America in days, a Swedish official said on Thursday. Lars-Erik De Geer, research director at the Swedish Defense Research Institute, a government agency, was citing data from a network of international monitoring stations established to detect signs of any nuclear weapons tests. Stressing that the levels were not dangerous for people, he predicted the particles would continue across the Atlantic and eventually also reach Europe.