Potential Alpha Energy Concentration PAEC

The exposure rate characteristic for this atmosphere is then given by the potential alpha energy concentration (PAEC) Ep... 

It has been demonstrated that it is possible to lower the level of airborne radon progeny by filtering and/or expose the air to an electric field. If the radiological risk is measured by the potential alpha energy concentration (PAEC) or exposure rate, for instance expressed in J m 3 or WL, the level may be lowered to about 10-20 % of the value in untreated air, while the reduced level may only be about 40-50 % of the untreated one if the average dose to a certain part of the respiratory tract, for instance expressed in Gy year 1, is considered. 

A better way to express the activity of the radon decay products is as the Potential Alpha Energy Concentration (PAEC). This quantity incorporates the deposition of energy into the air and is expressed as MeV/nr... 

The equivalent radon concentration (Xeq) is that concentration of 222Rn with decay products in equilibrium, which has the same potential alpha energy concentration (PAEC) as have the decay products actually present. Hence, if %eq = 1 Bq m-3, PAEC = 5.54 nJ m-3. 

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 ... 

Fig. 5.7. Relative size distribution in terms of potential alpha energy concentration, PAEC, of the unattached radon decay product clusters measured in indoor air.

Fig. 5.10. Typical relative activity size distribution of the potential alpha energy concentration, PAEC, of the radon decay product aerosols in room air. Ventilation <0.5 h , without aerosol sources. AMAD noted as AMDn = 40 nm, Sg = 1.7, fpn = 0.2 AMDa = 200 nm, , Sga = 2.2, /pa = 0.8.

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