Polonium 210 (abbreviated Po 210) is a radioactive element
138.4 days. It decays to lead
206 by emmission of an alpha particle
(alpha radiation). Richard Rhodes said, based upon its physical properties, " Polonium was a strange metal." The element " . . . emitted five thousand times as much radiation as an equivalent mass of radium
." This intense radiation is capable of causing the surrounding air to exhibit a blueish glow (Rhodes 578-580).
Po 210 alpha particles can be stopped by a thin layer of metal foil. During the Manhattan Project Po 210 was transported on platinum foil (itself sealed in a container). For unknown reasons Po is capable of migration outside a sealed container and " . . . can quickly contaminate large areas." It has been observed to travel against an air current, move from place to place without otherwise being acted upon, embed itself " . . . in the walls of shipping containers . . . ," and was used as part of the neutron initiator in the "Fat Man" atomic bomb (Rhodes 578-580).
Rhodes, Richard. The Making of the Atomic Bomb
. New York: Simon and Schuster, 1986.