Aspects of the motion of radioactive aerosol in electric fields are discussed. A revised estimate of the self-charging of radioactive aerosol in confined geometries is presented and used to estimate the self-generated electric field towards the wall. The enhancement of this field and decrease in negative ion concentration near the wall are calculated, but, in contrast to the atmospheric case, the extent of the enhanced region in confined geometries is shown to be very small. Consequently. aerosol removal by this field is likely to be negligible. Estimates are made of the strength of an imposed external field and the dimension of a confined geometry needed for effective removal of a radioactive aerosol from a gas stream. (C) 2008 Elsevier Ltd. All Fights reserved.