Recent articles (1-4)
have described the dangers to children and adults of secondhand cigarette
smoke. However, it is not widely known that cigarette smoke is substantially
Tobacco plants in the United States are
grown in soils and with high-phosphate fertilizers which are naturally
contaminated with the alpha-emitting radionuclide polonium-210 (Po-210).
(13-14) In addition, evidence exists that other atmospheric radon-222
(Rn-222) daughter products are also incorporated into the plant. (10,
15) The average cigarette contains 0.3 pCi of Po-210, (7) which is
melted, vaporized, inhaled, and ultimately deposited along the tracheobronchial
epithelial linings of smokers. (16-19).
In 1 year, a smoker
of 1 to 2 packs per day will irradiate portions of his or her bronchial
epithelium with about 8 to 9 rem. (8,16,18) This dose can be contrasted
with that from a standard chest x-ray film of about 0.03 rem. (20)
Thus, the average smoker
absorbs the equivalent of the dosages from 250 to 300 chest x-ray
films per year.
Worse, that energy is deposited along the short radiative tracks of
the alpha particles emitted, resulting in damage, destruction, mutation,
or all of these to adjacent bronchial epithelial cells. (21-24) Studies
(7,25,26) have been inconclusive in answering whether cigarette filters
are substantially effective in removing radioactive particles from
Considering that the
average smoker will absorb approximately
80 rem into the lung epithelial lining in about 10 years,
cancer can be anticipated as a prominent result of the habit.
content was first described in the mid-1960's. (8,16-18)
Subsequent studies (27,28) suggested
lesser dosage rates than those mentioned here. However, these rates
were proved to be erroneous. (18,19) Despite initial interest, little
has been published on the subject in recent years, and the radioactive
risks to children from secondhand smoke remain unknown.
Studies must be undertaken
to quantify Po-210 deposition in children of smoking parents. Until
then, smokers should be informed that they spend their days in radioactive
clouds and that they, their families, and friends are at potential
risk from those clouds of smoke.
I have observed that many parents who smoke,
on hearing of their unexpectedly large exposure to radiation from
smoking, have found the strength and motivation to quit the habit.
I hope that as this information becomes more widely known, fewer children
will suffer the ill effects of secondhand cigarette smoke and that
this potentially clinically significant exposure to radiation will