Alpha Radioactivity in Cigarette Smoke

The ..cap alpha.. activity of cigarette smoke tar deposited onto membrane filters was found to be associated with the relatively insoluble fraction. Perfusion of the tar with physiological saline resulted in no change in the mean measured activity, but there was more variability in the measured values for the perfused tar than for the initial tar samples. Analysis of cigarette smoke condensate shows that radium and thorium are present, but over 99% of the ..cap alpha.. activity results from /sup 210/Po. Repeat measurements after a time lapse of 2 1/2 years indicate that the initial /sup 210/Pb content of the tar is roughly 30 to 40% of the original /sup 210/Po content for both unprocessed and perfused samples. An increase in the ..cap alpha.. activity concentration of smoke deposited in lung tissue may result from the lack of solubility of the radioactive material compared with other smoke constituents.