Smoking does contribute additional radiation exposure to the body, which adds to the yearly natural radiation dose a person receives. This is because tobacco plants naturally absorb radioactive elements from the soil, such as uranium, radium, and especially radon progeny, which remain in the tobacco leaves and are inhaled when smoking.
To understand this, it’s important to recognize that humans are exposed to natural background radiation every year from cosmic rays, terrestrial sources, and internal radionuclides. This natural dose varies by location but typically averages around 2 to 3 millisieverts (mSv) annually. When a person smokes, they inhale not only chemical toxins but also radioactive particles attached to tobacco smoke.
The main radioactive contributors in tobacco smoke are isotopes of polonium-210 and lead-210, which are decay products of radon gas. Radon is a naturally occurring radioactive gas that seeps from the ground, and its decay products can attach to dust and tobacco leaves. When smoked, these radioactive particles lodge deep in the lungs, delivering localized alpha radiation doses that are significantly higher than the average background radiation dose to lung tissue.
This additional radiation dose from smoking is not trivial. Studies have estimated that a heavy smoker can receive an effective radiation dose to the lungs equivalent to several chest X-rays per year solely from the radioactive particles in cigarette smoke. This dose adds on top of the natural background radiation dose received by the body annually.
Moreover, the combined effect of smoking and exposure to radon gas in the environment is synergistic, meaning the risk of lung cancer is much higher than the sum of the individual risks. Radon exposure alone is a leading cause of lung cancer after smoking, and when combined with smoking, the radioactive particles inhaled from tobacco smoke exacerbate the damage to lung tissue.
In summary, smoking does add to the yearly natural radiation dose, particularly to the lungs, by introducing radioactive elements absorbed by tobacco plants. This radiation exposure contributes to the overall health risks of smoking, including the increased likelihood of lung cancer. The radiation dose from smoking is localized and can be significant compared to the natural background radiation dose, making it an important factor in tobacco-related health hazards.
