Dose conversion factors

MeV. WL-R = 100% x WL/radon concentrations (pCi/1). The dose conversion factor of 0.7 rad/working level month (WLM) (Harley and Pasternack, 1982) was used to calculate the mean absorbed dose to the epithelial cells and a quality factor (OF) of 20 was applied to convert the absorbed dose to dose equivalent rate. For example, from the average value of (WL) obtained from the arithmetic mean radon concentrations measured in the living area during winter and summer in South Carolina (Table I), the calculated dose equivalent rate is 4.1 rem/yr, e.g.,... 

The working level concept evaluates the unattached fraction and the activity median diameter in an indirect way, through the dose conversion factor. This paper will show that in the domestic environment this is mostly inaccurate to estimate the dose. 

The fraction of unattached daughters (fp), the equilibrium factor (F) and the activity median diameter (AMD) are plotted in Figure 6 for all the measurements. The AMD is derived from the aerosol measurements. These three parameters are important in the dosimetric models. At the top of Figure 6 the effective dose equivalent is plotted, computed with two models called the J-E (Jacobi-Eisfeld) and J-B (James-Birchall) models in the NEA-report (1983, table 2.9, linear interpolation between AMD=0.1 and 0.2 ym). The figure also shows the effective dose equivalent calculated from the equilibrium equivalent radon concentrations with the NEA dose conversion factor (NEA,1983, table 2.11). 

Wise, K.N., Dose Conversion Factors for Radon Daughters in Underground and Open-cut Mine Atmospheres, Health Phys. 43 53-64 (1982). 

Particle size is a major factor which determines the alpha dose conversion factor for radon daughters (mGy/WLM). Data on indoor environments are emerging and indicate that a variety of specific conditions exist. For example, a dose factor four times that for a nominal occupational or environmental exposure exists if kerosene heater particles dominate the indoor aerosol and four times smaller if a hygroscopic particle dominates. 

Due to the superposition of various other biological, physiological and physical parameters used in modelling, the published exposure-dose conversion factors range from 2 to 120 mGy per WLM. However, a sensitivity analysis indicated that for most indoor exposure situations compensatory effects can reduce this range to about 5 to 10 mGy/WLM for the indoor situations occurring most frequently (OECD/NEA, 1983). 

A third possibility consists of comparing the theoretically calculated lung cancer rate based on risk coefficients derived from miners with the actual cancer occurrence among non-miners, derived from Rn-d exposure assessment in dwellings and using appropriate exposure-dose conversion factors (Steinhausler et al.. 1983 ... 

EPA. 1988. Limiting values of radionuclide intake and air concentration and dose conversion factors for inhalation, submersion, and ingestion. Federal Guidance Report No. 11. Washington, DC U.S. Environmental Protection Agency, Office of Radiation Programs. EPA-520/1-88-020. 

By considering all possible transfer routes, one can estimate what amount of a radionuclide released to the environment may end up in plants, animals, or man. When these figures are combined with the dose conversion factors ("committed effective dose equivalent per unit intake", according to ICRP) in Table 18.12, it is possible to calculate the dose received by man from intake of a radionuclide in the environment. The dose conversion factors dep d on the mode of intake (usually only inhalation or ingestion). Thus... 

Ihe dosimetric consequence of particle size determination is tiiat a realistic bronchial dose may be calculated (13). In tiiis case, essentially the same dose conversion factor applies at both Femald and at the residential home in New Jersey because the median diameter is identical. UNSCEAR 2000 (14) gives the... 

A few of the doses were calculated with an older version of the code (MACCS Version 1.5.11.1) and dose conversion factor library using the same input parameters. Both versions of the code and dose conversion factor library gave almost identical results for these inputs. Further details on the calculation method and inputs can be found in the MACCS2 user manual (Chanin and Young 1997) and in the airborne dose versus distance database documentation (Naegeli 1999). 

Radionuclide Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion, and Ingestion, Federal Guidance Report 11, EPA 520/1-88-020, second printing with corrections. Environmental Protection Agency, Washington, DC, 1989. 

For Tc, probably present as pertechnetate, the concentration factor (CF) varies according to biological species (Table 3). The CF is high for seaweed ( 10 ) and low for fish fillet ( 10). For lobster (tail muscle) recent results showed that the CF is 10, which is a factor of 10 higher than previously measured in laboratory experiments. For edible parts of mussels and oysters, the CF is about 500 and 300, respectively. After the ingestion of contaminated lobster from the Irish Sea, 4-7% of Tc was retained in the body lyear after intake. Thus, there seems to be a long-term compartment in the body retaining Tc and the dose conversion factor should be revised. 

Posterndorfer J, Reineking A (1999) Characteristics in air and dose conversion factor. Health Phys 76 300-305... 

Federal Guidance Report No. 11 (Eckerman, Wolbarst, and Richardson, 1988) provides dose conversion factors (DCFs) also based on ICRP 26 that allow one to calculate the whole body... 

In the estimation of the dose conversion factor, DCF, by dose model calculations, the activity size distribution in terms of potential alpha energy concentration (PAEC) is an important input parameter. For practical reasons related to measurements, the activity size distribution should be divided into three parts as follows ... 

The dose conversion factor, DCF, in effective dose per exposure unit is calculated by taking into account the dose function of the particle diameter (Figure 5.4) and the radon decay product characteristics. The dose conversion factors for living and work places with typical activity size distributions, as a function of the unattached fraction, fp, are illustrated in Figures 5.13 and 5.14, respectively. The value of the dose conversion factor, DCFae, for fp = 0 represents the dose contribution of the radon product aerosols. The values of dose conversion factor in Figure 5.14 are based on aerosol conditions which are typical for many workplaces. 

Fig. 5.13. Dose conversion factor, DCF, as a function of the unattached radon decay product clusters in indoor air (—) and outdoor air (—). The DCFae value is the dose fraction by the aerosol. Indoors, v = 0.75 h (no coarse...

Fig. 5.14. Dose conversion factor, DCF, as a function of the unattached radon decay product clusters for working...

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