Activity size distribution and chemical state of atmospheric aerosol particles as a carrier of radioactive materials

Radioactive materials were released to the environment due to the Fukushima Daiichi Nuclear Power Plant accident in March of 2011. It is important for us to solve the problems concerning migration and diffusion processes of radioactive materials in the environment. So we tried to estimate the particle size distributions of atmospheric aerosols attached ⁷Be and the chemical state of atmospheric aerosol particles as a carrier of radioactive materials. We found that there mainly exist F^-, Cl^-, NO₃^- and SO₄^2- in aerosol particles in air, as far as anions included are concerned. Average particle size of aerosols including SO₄^2- was estimated to be 0.54 μm. In addition, it was found that the particle size distribution of aerosols including SO₄^2- closely resembles that of ⁷Be-aerosols. So, we conjecture that sulfate would be the potential transport medium for ⁷Be. (author)