Study on radon and radon progeny in some living rooms

Abstract

In the first part of this work, the potential alpha energy concentration (PAEC) of radon progeny, the equilibrium factor (F), the activity concentration of 222Rn gas (Co) and the unattached fraction (fp), were determined in 15 living rooms at El-Minia City, Egypt. The activity size distribution of (214)Pb was measured by using a low pressure Berner impactor. Based on the parameters of that distribution the total effective dose through the human lung was evaluated by using a dosimetric model calculation of ICRP. An electrostatic precipitation method was used for the determination of 222Rn gas concentration. The mean activity concentration of 222Rn gas (Co) was found to be 123 +/- 22 Bq m(-3). A mean unattached fraction (fp) of 0.11 +/- 0.02 was obtained at a mean aerosol particle concentration (Z) of (3.0 +/- 0.21) x 10(3) cm(-3). The mean equilibrium factor (F) was determined to be 0.35 +/- 0.03. The mean PAEC was found to be 37 +/- 8.1 Bq m(-3). The activity size distribution of (214)Pb shows mean activity median diameter of 290 nm with mean geometric standard deviation (sigma) of 2.45. At a total deposition fraction of approximately 23% the total effective dose to the lung was determined to be approximately 1.2 mSv. The second part of this paper deals with a study of natural radionuclide contents of samples collected from the building materials of those rooms under investigation given in part one of this paper. Analyses were performed in Marinelli beakers with a gamma multichannel analyser provided with a NaI(Tl) detector. The samples have revealed the presence of the uranium-radium and thorium radioisotopes as well as (40)K. Nine gamma-lines of the natural radioisotopes that correspond to 212Pb, 214Pb, 214Bi, 228Ac, 40K and 208Tl were detected and measured. The activity concentrations of 226Ra, 232Th and 40K were determined with mean specific activities of 65 +/- 22, 35 +/- 12 and 150 +/- 60 Bq kg(-1), respectively. These activities amount to a radium equivalent (Ra(eq)) of 126 Bq kg(-1) and to a mean value of external hazard index of 0.34.

ICRP Publication 137: Occupational Intakes of Radionuclides: Part 3

“…This depends on ventilation rate and whether or not additional aerosol sources are present. Mean values of f p measured in dwellings range between 4% and 20%, with some values greater than 40% (Chen et al., 1998; Kojima and Abe, 1988; Reineking and Porstendörfer, 1990; Hopke et al., 1995; Tokonami et al., 1996a; Yu et al., 1996; Vargas et al., 2000; Huet et al., 2001a,b; El-Hussein, 2005; Mohammed, 2005; Kranrod et al., 2009; Guo et al., 2012). Measurements of f p in indoor workplaces, such as schools and offices, also show a wide range of values, typically between 3% and 15%, and with some values greater than 20% (Hattori and Ishida, 1994; Hattori et al., 1995; Tokonami et al., 1996b; Yu et al., 1998; Porstendörfer, 2001; Vaupotič, 2008b; Guo et al., 2012).…”

Deposition pattern of inhaled radon progeny size distribution in human lung

“…With monodisperse liquid radioactive labeled aerosol particles in the diameter size range 70e6000 nm, the 50% cut-off diameters of the impactor stages were determined to be 82, 157, 270, 650, 1100, 2350, 4250 and 5960 nm (Reineking, 1984). More description about this procedure was given by Mohamed (Mohammed, 1999;Mohamed, 2006).…”

Influence of aerosol particle concentration on volumetric activities of indoor radon progeny

“…Thus, there are more dangerous radon short-lived decay products in a "dusty" room than in a "clean" room with the same concentration of radon in the air [1,2].…”

“…There are two forms of decay products: "unattached to aerosol particles" (the diameter of their diffusion equivalent is from 0.5 to 5 nm), and "attached to aerosol particles" (diameter from 5 to 3000 nm) [2].…”