Highly Time-Resolved Measurements of Airborne Radionuclides by Extremely Low Background γ-ray Spectrometry

Their Variations by Typical Meteorological Events

Abstract

In order to investigate variation of concentrations of airborne radionuclides, ²¹⁴Pb, ²¹²Pb, ⁷Be, and ²¹⁰Pb, accompanied with a typical meteorological event, such as passage of cold front, approach of typhoon, and Asian dust (Kosa), highly time-resolved (2-6 hours) measurements of natural radionuclides were performed by ultra low background γ-ray spectrometry. Surface air concentrations of these nuclides showed characteristic temporal changes by each meteorological phenomenon. In addition, variation patterns were found to be obviously different between short-lived ²¹⁴Pb and ²¹²Pb and long-lived ⁷Be and ²¹⁰Pb. One of causes of the difference might be explained by difference of their sources: local for short-lived nuclides and regional for long-lived ones.