Title: Analysis of Radionuclide Releases from the Fukushima Dai-ichi Nuclear Power Plant Accident Part II
Source: Pure and Applied Geophysics
Authors: Pascal Achim, Marguerite Monfort, Gilbert Le Petit, Philippe Gross, Guilhem Douysset, Thomas Taffary, Xavier Blanchard, Christophe Moulin
Date: September 2012

[...] In this study, the emissions of the three fission products Cs-137, I-131 and Xe-133 are investigated.

[...] worldwide industrial Xe-133 background could be modified by Fukushima radioxenon release affecting the performances of the CTBT radionuclide monitoring network.

[...] during the couple of months after the Fukushima Dai-ichi accident, monitoring capabilities of the network could have been affected by the large amount of radioxenon released by the accident. The impact of Fukushima radioxenon releases on the worldwide Xe-133 background must also be investigated. [...]

The maps below show the activity concentration of Xe-133 at ground-level on March 31, 2011 (top) and May 10, 2011 (bottom)

Full analysis in here