Radon moderate ventilation

The results of these measurements show that the fraction of the free radon daughters in rooms with low and moderate ventilation and without any aerosol sources are higher (fp = 0.06 - 0.15) than proposed in literature (Jacobi and Eisfeld, 1980 ICRP 32, 1981 NEA, 1983). A mean value of 10 % (fp = 0.1) was determined. Only additional aerosol sources in a room such as cigarette smoke, cooking, candle light or stove heating led to a decrease of the fp-value below 0.05. 

Table IJa. The aerosol concentration (Z), the activity concentrations of radon (cj) and the free (cjf, C2 ) and attached (c a, c 3, C3 ) radon daugthers, measured in rooms i/ith moderate ventilation (partly opened windows).

The measurements were performed at four different locations with radon concentrations ranging from 7 to 111 Bq/nr and with low to moderate ventilation rates. The main characteristics of the locations are listed in Table I. 

In Figure 8 the doses per unit radon concentration are plotted as a function of the measured ventilation rate. The NEA conversion factor for low and moderate ventilation (NEA,1983, table 2.10) is multiplied by the appropriate equilibrium factor. In the figure no influence of the ventilation rate on the doses is found. 

The paper summerizes the experimental data on the equilibrium factor, F, the free fraction, fp, the attachment rate to the room air aerosol, X, the recoil factor,, and the plateout rates of the free, qf, and the attached, q3, radon daughters, determined in eight rooms of different houses. In each room several measurements were carried out at different times, with different aerosol sources (cigarette smoke, stove heating etc.) and under low (v<0.3 It1) and moderate (0.3[Pg.288]

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