Simultaneous sampling of indoor and outdoor airborne radioactivity after the Fukushima Daiichi nuclear power plant accident.
Several studies have estimated inhalation doses for the public because of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Most of them were based on measurement of radioactivity in outdoor air and included the assumption that people stayed outdoors all day. Although this assumption gives a conservative estimate, it is not realistic. The "air decontamination factor" (ratio of indoor to outdoor air radionuclide concentrations) was estimated from simultaneous sampling of radioactivity in both inside and outside air of one building. The building was a workplace and located at the National Institute of Radiological Sciences (NIRS) in Chiba Prefecture, Japan. Aerosol-associated radioactive materials in air were collected onto filters, and the filters were analyzed by γ spectrometry at NIRS. The filter sampling was started on March 15, 2011 and was continued for more than 1 year. Several radionuclides, such as (131)I, (134)Cs, and (137)Cs were found by measuring the filters with a germanium detector. The air decontamination factor was around 0.64 for particulate (131)I and 0.58 for (137)Cs. These values could give implications for the ratio of indoor to outdoor radionuclide concentrations after the FDNPP accident for a similar type of building.
National Institute of Radiological Sciences , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
Tetsuo
T
Ishikawa
Atsuyuki
A
Sorimachi
Hideki
H
Arae
Sarata Kumar
SK
Sahoo
Miroslaw
M
Janik
Masahiro
M
Hosoda
Shinji
S
Tokonami
D000396:Air Pollutants, Radioactive / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis; D062406:Fukushima Nuclear Accident; D007564:Japan; D055848:Nuclear Power Plants; D011834:Radiation Monitoring / Q000379:methods*; D011851:Radioactivity; D011868:Radioisotopes / Q000032:analysis; D013051:Spectrometry, Gamma
D000396:Air Pollutants, Radioactive; D011868:Radioisotopes