Radon daughters

Radon (Rn) and Radon Decay Products Radon is a radioactive gas formed in the decay of uranium. The radon decay products (also called radon daughters or progeny) can be breathed into the lung where they continue to release radiation as they further decay. 

Radon daughters The series of unstable isotopes that are formed as radon atoms undergo radioactive decay. 

Working level (WL) The allowable level ot exposure of a person to an atmosphere that contains any combination of Radon daughters. 

Working level month (WLM) An exposure ot I WLM can be taken to be received by a person working in a Radon daughter concentration of 1 WL for 170 hours. 

Polian G, Lambert G (1979) Radon daughters and sulfur output from Erebus volcano, Antaitica. J Volcanol Geotherm Res 6 125-137... 

Unattached Fraction—That fraction of the radon daughters, usually 218Po and 214Po, which has not yet attached to a dust particle or to water vapor. As a free atom, it has a high probability of being exhaled and not retained within the lung. It is the attached fraction which is primarily retained. 

Working Level (WL)—Any combination of short-lived radon daughters in 1 liter of air that will result in the ultimate emission of 1.3x105 MeV of potential alpha energy. 

Working Level Month (WLM)—A unit of exposure to radon daughters corresponding to the product of the radon daughter concentration in Working Level (WL) and the exposure time in nominal months (1 nominal month =170 hours). Inhalation of air with a concentration of 1 WL of radon daughters for 170 working hours results in an exposure of 1 WLM. 

James A. 1987. A reconsideration of cells at risk and other key factors in radon daughter dosimetry. In Hopke P, ed. Radon and its decay products Occurrence, properties and health effects. ACS Symposium Series 331. Washington, DC American Chemical Society, 400-418. 

Cohen, B.S., Deposition of Ultrafine Particles in the Human Tracheobronchial Tree A Determinant of the Dose from Radon Daughters, this volume (1987). 

Harley, N.H. and B.S. Cohen, Updating Radon Daughter Bronchial Dosimetry, this volume (1987). 

Jonassen, N., Electrial Properties of Radon Daughters, presented to the International Conference on Occupational Radiation Safety and Mining, Toronto, Canada (1984). 

Jonassen, N. and J.P. McLaughlin, The Reduction of Indoor Air Concentrations of Radon Daughters Without the Use of Ventilation,... 

Porstendorfer, J., A. Reineking, and K.H. Becker, Free Fractions, Attachment Rates and Plateout Rates of Radon Daughters in Houses, this volume (1987). 

Steinhausler, F., On the Validity of Risk Assessments for Radon Daughters Induced Lung Cancer, this volume (1987). 

Vanmarcke, H., A. Janssens, F. Raes, A. Poffijn, P. Berkvens, and R. Van Dingenen, On the Behavior of Radon Daughters in the Domestic Environment and Its Effect on fht Effective Dose Equivalent, this volume (1987). 

George, A. C. and Breslin, A. J. The Distribution of Ambient Radon and Radon Daughters in Residential Buildings in the New Jersey - New York Area. Natural Radiation Environmental III, Vol. 2, C0NF-780422, Technical Information Center, U. S. Department of Energy, Springfield, VA (1980). 

A Time Integrating Environmental Radon Daughter Monitor, Health Phvs. 36 452 (1979). 

Harley, N., and B. C. Pasternack, Environmental Radon Daughter Alpha Dose Factors in a Five-Lobed Human Lung, Health Phvs. 42 789 (1982). 

Jacobi, W. and Paretzke H.G. 1985, Risk Assessment for Indoor Exposure to Radon Daughters, In Proceedings, Seminar on Exposure to Enhanced Natural RAdiation and Its Regulatory Implications, Maastricht, the Netherlands, March 25-27, Elsvier Science Publisher, Amsterdam. 

Kusnetz H.L., 1956, Radon Daughters in Mine Atmospheres, a Field Method for Determing Concentrations, Ind.Hyg.Quart., 17, 85-88. 

Lundin R.E., Wagoner J.K. and Archer V.E., 1971, Radon Daughter Exposure and REspiratory Cancer-Quantitive and Temporal Aspects,... 

Relation Between Long-Term Exposure to Radon Daughters, Proceed,... 

Sevc J., Kunz E. and Placek V., 1976, Lung Cancer in Uranium Miners and Long-Term Exposure to Radon Daughter Products, Health Phys.,... 

Swedjemark G.A. and Mj0nes L., 1984, Radon and Radon Daughter Concentrations in Swedish Hones, Radiation Protection Dosimetry,... 

The ventilation rate has decreased since the 1950s indicating a higher equilibrium factor and thereby a higher radon daughter increase since the 1950s than the increase of the radon gas concentration. How the particle concentrations have changed is not known. 

In Sweden, requirements on future building (Swedjemark, 1986) and the limits for existing dwellings will result in lower radon daughter concentrations in homes and to some part it already has. 

For the collective dose, however, the decrease will be very slow because of the low building rate compared with the housing stock. It has been estimated tha the average for the Swedish radon daughter concentration, 50 Bq/m EER, may be decreased to half that value after about 100 years, if the requirements mentioned above are fulfilled. 

In most other countries regulations or recommendations for a decrease of the radon daughter concentrations in homes have not been established. In USA and Canada limits have been given only for special cases, for example building on waste from uranium and phosphate industries (Atomic Energy Control Board, 1977 EPA, 1979 EPA, 1980). In Finland, there are general recommendations for homes (Finnish Radon Commission, 1982). 

G.A., Calibration, Radon and Radon Daughters in Air, Report a 82-22, National Institute of Radiation Protection, Stockholm (1982) (in Swedish). 

Swedjemark, G.A. and MjOnes, L. Exposure of the Swedish population to radon daughters, in Proceedings of the 3rd International Conference on Indoor Air Quality and Climate, Stockholm, 1984, 2, pp. 37-43, Swedish Council for Building Research, Stockholm (1984). 

Swedjemark, G.A., Radon and its decay products in housing - estimation of the radon daughter exposure to the Swedish population and methods for evaluation of the uncertainties in annual averages, Thesis, Department of Radiation Physics, University of Stockholm (1985). 

Wolfs, F., Hofstede, H., deMeijer, R.J. and Put, L.W., Measurements of radon-daughter concentrations in and around dwellings in the northern part of the Netherlands a search for the influences of building materials costruction and ventilation. Health Phys, 47 ... 

Castren, 0., The contribution of bored wells to respiratory radon daughter exposure in Finland. Proc. of Symposium on Natural Radiation Environment, (C0NF- 780422, vol.2.) pp. 1364-1370, Houston, Texas (1978). 

Cliff, K.D., Assessment of Airborne Radon Daughter Concentrations in Dwellings in Great Britain, Phys. Med. Biol. 23 696-711 (1978a). 

Indoor air radon concentrations measured in a randomly selected sample of 220 Irish houses have been found to range from about 20 Bq/nr to as high as 1740 Bq/nr with a median value of 61 Bq/nr. Using current dose estimation methods the estimated effective dose equivalents due to radon daughter inhalation in these houses are 1.6 mSv/year (median value) and 46 mSv/year (maximum value). 

Integrating alpha track based passive detectors, which yield both a measurement of the mean radon concentration and of the radon daughter equilibrium (F) in each house, are being used in this national survey. 

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