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Home | Did You Know?Polonium-210 and Cigarette SmokeAccording to NCRP Report No. 95, Radiation Exposure of the U.S. Population from Consumer Products and Miscellaneous Sources (1987), deposition of 210Po in the lungs of cigarette smokers results in an average annual dose equivalent of 0.16 Sv (16 rem) to the segmental bifurcations of the bronchial epithelium. Although the data necessary for converting this to an effective dose equivalent are not available, based on information given in Publication 32 of the International Commission on Radiological Protection (ICRP, 1981) a weighting factor of 0.08 appears to be a reasonable estimate. This would yield an annual effective dose equivalent to the average smoker of about 13 mSv (1,300 mrem); the corresponding average population effective dose equivalent would be 2.8 mSv y–1 (280 rnrem y–1). Had this approach been utilized, it would have resulted in tobacco products being the greatest contributor to the effective population dose equivalent of all consumer products. In fact, tobacco products probably would have been the greatest single contributor to the effective population dose equivalent of all radiation sources, including natural background sources and medical radiation [NCRP Report No. 93 summarizing exposures from all sources (NCRP, 1987a)]. Because of the widespread recognition that a high risk of lung cancer is associated with smoking, and because the effective dose equivalent from this source is likely to be so far in excess of that from any other consumer product, it would appear mandatory to call for more detailed monitoring and evaluation of the dose equivalent from this source. Studies indicate that smokers face a risk of fatal lung cancer of about 3 to 9 % while for nonsmokers the same risk is only about 0.5 % (Boice and Blot, 1986): The risk associated with an effective dose equivalent of 13 mSv y–1 (1.3 rem y–1) would, in 50 y, amount to about 1 %. This is evidently only a portion of the risk for smokers. Whether 210Po is a contributing factor in the development of lung cancer (such as an initiator or promoter) can only be conjectured at this time. Get the full report and references at: http://NCRPpublications.org NCRP Report No. 93 is being updated by NCRP Scientific Committee 6-2, Radiation Exposure of the U.S. Population, including the information on radiation exposure from consumer products such as tobacco: http://www.ncrponline.org/Current_Prog/SC_6-2.html
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