title: Novel method for estimation of the indoor-to-outdoor airborne radioactivity ratio following the Fukushima Daiichi Nuclear Power Plant accident.
abstract: The accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in Japan resulted in significant releases of fission products. While substantial data exist concerning outdoor air radioactivity following the accident, the resulting indoor radioactivity remains pure speculation without a proper method for estimating the ratio of the indoor to outdoor airborne radioactivity, termed the airborne sheltering factor (ASF). Lacking a meaningful value of the ASF, it is difficult to assess the inhalation doses to residents and evacuees even when outdoor radionuclide concentrations are available. A simple model was developed and the key parameters needed to estimate the ASF were obtained through data fitting of selected indoor and outdoor airborne radioactivity measurement data obtained following the accident at a single location. Using the new model with values of the air exchange rate, interior air volume, and the inner surface area of the dwellings, the ASF can be estimated for a variety of dwelling types. Assessment of the inhalation dose to individuals readily follows from the value of the ASF, the person's indoor occupancy factor, and the measured outdoor radioactivity concentration.
authors.affiliation: College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang, Hunan Province, China. Electronic address: hytyl@163.com.
authors.forename: Yanliang
authors.initials: Y
authors.lastname: Tan
authors.affiliation: Fukushima Medical University, 1 Hikariga-oka, Fukushima, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Regulatory Science Research Program, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Miroslaw
authors.initials: M
authors.lastname: Janik
authors.affiliation: Department of Radiation Physics, Institute of Radiation Emergency Medicine, Hirosaki University, Hirosaki, Aomori, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Tokonami
authors.affiliation: Hirosaki University Graduate School of Health Science, Hirosaki, Aomori, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hosoda
authors.affiliation: Fukushima Medical University, 1 Hikariga-oka, Fukushima, Japan.
authors.forename: Atsuyuki
authors.initials: A
authors.lastname: Sorimachi
authors.affiliation: Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Kimberlee
authors.initials: K
authors.lastname: Kearfott
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D062406:Fukushima Nuclear Accident; D007564:Japan; D011834:Radiation Monitoring; D012044:Regression Analysis
chemical_list: D000396:Air Pollutants, Radioactive
keywords: Air exchange rate; Airborne sheltering factor; Indoor airborne deposition velocity