Table IV. Summary of Numerical Conversions for Radon and Thoron Quantities, Regardless

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DOE-STD-1121-98
Table IV. Summary of Numerical Conversions for Radon and Thoron Quantities, Regardless of
the Precision of Measurements
In Units
In Units
Multiply
Of
By
To Obtain
Of
:Ci/mL
Concentration, C
pCi/L
0
Concentration, C
Ambient 222Rn or 220Rn
pCi/L
F*
Equilibrium equivalent
pCi/L
222
Rn or 220Rn
concentration, C
concentration, EEC
222
Rn EEC
pCi/L
1/100 = 0.01
Potential alpha energy
WL
concentration, PAEC
220
Rn EEC
pCi/L
1/(7.43) = 0.13459
PAEC
WL
222
Rn or 220Rn progeny
WL
Exposure time,
Potential alpha energy
WLM
PAEC
t (hours) ÷170
exposure, PAEE
Integrated 222Rn
F × 1.4118E!3
PAEE
WLM
concentration, NV (ambient)
Integrated 222Rn
5.6471E!4
PAEE
WLM
concentration, NV (ambient)
assuming F = 0.4
222
Rn PAEE
WLM
5/4 = 1.25
HE,50
rem
222
DACAh
Rn PAEE
WLM
2000/4 = 500
E (exposure)
5/12 = 0.4333'
220
Rn PAEE
WLM
3
HE,50
rem
2000/12 = 166.6'
220
DACAh
Rn PAEE
WLM
6
E (exposure)
1/0.12 = 8.333'
HE,50 for 222Rn or 220Rn
rems
3
Hlung,50
rem
4.2490E!3
PAEC
WLM
Potential alpha energy
J
intake, I, of 222Rn or 220Rn
progeny
*For 222Rn, Fdefault = 0.4; for 220Rn, Fdefault = 0.04
7.5.6 Possible Values of DACs for Pure Radon and Thoron Gas
Neither the IAEA nor the EPA, NRC, or DOE have set standards for inhalation of pure radon or
thoron such as may be found inside an air-purifying respirator. However, the ICRP in its 1981
Publication 32 did set such standards based on limitation of stochastic risk and on dosimetry. The 1981
ICRP DAC for 222Rn without progeny is 1.5E5 BqAm!3, while that for 220Rn + 216Po (which are essentially
in equilibrium due to the 0.145-s half-life of 216Po) is 2.5E5 BqAm!3. These values are based in the same
inferential system as the ALIs of 0.02 J and 0.06 J, respectively, for radon and thoron progeny. Since that
system deduces values of 4.8 WLM and 14.4 WLM as ALEs for radon and thoron progeny, the
concentrations should be scaled by the ratio of 5/6 (= 4/4.8 = 12/14.4) to arrive at concentrations suitable
for comparison to the DOE system. Furthermore, these DACs are described as being exactly 100 and 500
85

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