Abstract: ²¹⁰Pb and ²¹⁰Po in aerosol are in disequilibrium and separated by the short-lived radionuclide ²¹⁰Bi. The initial activity concentration of ²¹⁰Bi is often unknown, and the ²¹⁰Po activity concentration in aerosol is difficult to be estimated to the initial sampling time. This article analyzes the effect of the short-lived radionuclide ²¹⁰Bi upon the calculation of activity concentration of ²¹⁰Po. In most of the actual conditions, the activity concentration ratios of ²¹⁰Po/²¹⁰Pb in air are less 1, and the ratio of ²¹⁰Bi/²¹⁰Pb in air should be considered and ²¹⁰Bi needs to be measured quickly within one month. Otherwise, ²¹⁰Bi/²¹⁰Pb cannot be measured. It is recommended to take short-time sampling, rapid measurement and other measures to avoid such errors when the activity concentration of ²¹⁰Bi in the initial air is unknown.

Key words: air aerosols, ²¹⁰Bi, ²¹⁰Pb, ²¹⁰Po