Answer to Question #8521 Submitted to "Ask the Experts"

Can you tell me what is the calculated effective dose equivalent or committed effective dose to the lungs from smoking one pack of cigarettes (20 cigarettes per pack) or direct me to a website or reference that can?

Smoking one 20-cigarette pack would result in an effective dose, E, of about 1 µSv. This compares to a natural background level of about 3 mSv per year. Understand that this is subject to a large amount of uncertainty since the radioactivity content of a cigarette varies; the physiological parameters such as inhalation, lung capacity, and a host of other factors would affect this estimate as well. 

A more comprehensive answer is provided below by Ray Johnson:

Information on radioactivity in tobacco products was recently reported in a book by the National Council on Radiation Protection and Measurements (NCRP), Ionizing Radiation Exposure of the Population of the United States, Report No. 160, 3 March 2009.

Chapter 5 of this book addresses consumer products and activities. Tobacco products are discussed on pages 156–162. Many factors will affect the radiation dose that may result from smoking cigarettes. The first has to do with the quantity of radioactive elements in the tobacco, especially polonium-210 and lead-210. These two radionuclides may be collected from airborne deposition on tobacco leaves or taken up from the ground through the root system. The amount of these nuclides inhaled also depends on the amount transferred from the tobacco to the smoke or absorbed on filters. The amount retained in the lungs depends on the particle size and other factors. 

Ashraf Khater (2004) determined that about 50% of the polonium-210 inhaled is retained in the smoker's lungs and a one-pack smoker would inhale about 120 mBq each of polonium-210 and lead-210. 

Donatella Desideri and colleagues (2007) estimated that 20 cigarettes would result in an inhalation of 80 +/- 30 mBq each of polonium-210 and lead-210. 

From these data, 100 mBq per pack of cigarettes is a reasonable estimate for intake of each radionuclide, polonium-210 and lead-210. When these radionuclides are inhaled, they may be deposited on lung tissues (bronchial epithelium), especially in the areas of branching or bifurcation of airways in the lower lung. Emission of alpha-particle radiation from polonium-210 can cause damage to growing cells near the surface of lung tissues. Depending on solubility of the radionuclides, they may also be carried to other organs including the kidney, liver, bone marrow, and spleen. 

To determine the total effective dose (to all parts of the body), one has to consider the direct deposition of alpha-particle energy in lung tissues and the dose to various organs that may result from polonium-210 and lead-210 absorbed in the blood stream and carried to other parts of the body. Report 160 (Table 5.6) gives an average annual effective dose of 18 uSv for one cigarette per day. At one pack of 20 cigarettes a day, the annual effective dose would be 360 µSv. On this basis, a single pack of 20 cigarettes would result in an effective dose of 1 µSv. For comparison, 360 µSv per year for a pack-a-day smoker gives an effective dose similar to what everyone receives on the average from outer space at 330 µSv per year or from the ground at 210 µSv per year (Table 2.1). 

Ray Johnson, MS, PE, FHPS, CHP
(Author of the section on tobacco products in NCRP Report 160)

Orhan H. Suleiman, MS, PhD

References
National Council on Radiation Protection and Measurements. Ionizing radiation exposure of the population of the United States. Bethesda, MD: National Council on Radiation Protection and Measurements; NCRP Report No. 160; 2009.

Desideri  D, Meli MA, Feduci L, Roselli C. ²¹⁰Po and ²¹⁰Pb inhalation by cigarette smoking in Italy. Health Physics 92(1); 2007.

Khater AEM. Polonium-210 budget in cigarettes. J Environ Radioact 71(1):33–41; 2004.