A new approach for reconstructing the I-spreading due to the 2011 Fukushima nuclear accident by means of measuring I in airborne particulate matter.

To retrieve the diffusion trajectory of the I dispersed in the environment by the nuclear power plant accident in Fukushima in 2011, airborne particulate matter (APM) samples collected in the Tokyo metropolitan area were analyzed for their I contents by means of accelerator mass spectrometry. In evaluating blank levels of chemicals and filters used for collecting APM, we established the analytical procedure for determining the I activity of as low as 10 Bq for a small piece of filter samples (about 0.1 cm).