Concentration of Pb-214 and Bi-214 in the Atmosphere at Kasetsart University

Abstract

By gamma spectrometry of dusts in the atmosphere, the natural radioisotopes ²¹⁴Pb and ²¹⁴Bi were found. Samples of air were examined to ascertain the concentration per unit volume. Air particles were collected on fibre glass filters using a high volume jet air sampler. The two hundred-seventy air samples from six different locations at K.U. were monitored for gamma activities by a Hyper Pure Germanium (HPGe) detector. The gamma spectra were then examined and analyzed by microcomputer. The average concentrations of ²¹⁴Pb and ²¹4Bi in the atmosphere at K.U. were found to be (5.79±0.62) x 10^-12 µgm/m³ and 1.61±0.31) x 10^-11 µgm/m³ respectively. Safety standard of maximum concentration of ²¹⁴Pb or ²¹⁴Bi in the atmosphere is 1 x 10^-6 µgm/m³ . The results show that the concentration of these isotopes is lower than the maximum of the safety standard.