Table XV. Radon Equilibrium Factors Indoors at Home

DOE-STD-1121-98

In Table XV are 16 results of studies of FRn indoors, along with four recommendations for a default

or assumed value (UNSCEAR 1988; UNSCEAR 1993; Porstendrfer and Reineking 1992; NCRP

1987a). Earlier data did not account for smoking, which is known to increase FRn and decrease the

unattached fraction, fp. In cleaner indoor, air, lower values of FRn are observed (UNSCEAR 1993;

Swedjemark 1983; NEA 1985). Observed values range from 0.04 to 0.97, with an average value of 0.43

and average ranges from 0.17 to 0.71. Since these measurements were made under very different

circumstances, the wide range of values is not surprising. Most recommended values are 0.4, with one of

0.3. The ICRP has adopted 0.4 (ICRP 1993a).

Table XV. Radon Equilibrium Factors Indoors at Home

Country

avg

min max Reference

Environment

Rec.

Austria

0.60

Steinhausler et al. 1980

Australia

0.32 0.09

0.17 0.49 Solomon and Ren (1992)

Bangladesh

0.40 0.23

0.04 0.97 Farid (1993)

Canada

0.35

0.17 0.65 McGregor and Gourgon (1980)

18 cities

Canada

0.41

Scott (1983)

Finland

0.47

0.30 0.63 Makelainen (1980)

France

0.26

0.10 0.48 Tymen et al. (1992)

Norway

0.50

0.30 0.80 Stranden et al. (1979)

Sweden

0.44

0.10 0.80 Swedjemark (1983)

Sweden

0.51

Jonassen and McLaughlin (1989)

smoker

Sweden

0.46

Jonassen and McLaughlin (1989)

nonsmokers

USA

0.63

George and Breslin (1980)

living areas

USA

0.33

Israeli (1985)

living areas

West Germany

0.37

0.25 0.65 Wicke and Porstendorfer (1982)

West Germany

0.34

0.10 0.90 Keller and Folkerts (1984)

Yugoslavia

0.55

Planinic and Faj (1990)

0.17 0.71 All Studies

AVERAGE

0.43

0.09 0.17 All Studies

Std. Dev.

0.11

All Studies

Min of Minima

0.04

All Studies

Max of Maxima

0.97

No. Studies

recommendation

UNSCEAR (1988) Annex A para 140

0.4

recommendation

UNSCEAR (1993) Annex A para 118

0.4

summary

0.20

0.40 Porstendorfer and Reineking (1992)

0.3

recommendation

NCRP (1987)

0.4

The workplace may have different aerosol characteristics from the home (either cleaner or dirtier).

However, few measurements of FRn in the workplace are available. Two Japanese authors (Hattori and

Ishida 1994) measured the equilibrium factor of 222Rn in a pressurized water reactor auxiliary building for

a year. In this clean, well-ventilated workplace, they observed a mean of 1,993 measurements of F =

0.28 + 0.09, with the lognormally distributed unattached fraction median fp = 0.069 with a GSD = 1.8. In

a boiling water reactor turbine building, they observed that the mean of 2,555 equilibrium factor

measurements was F = 0.32 + 0.10 with a lognormally distributed unattached fraction median fp = 0.056

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