3. Results
The effect of the humidity in the environmental atmosphere on
exhalation rates for the two different materials –brick (upper
graphs) and granite (lower graphs) can be seen inFigs. 4 and 5for
radon and thoron, respectively. TheRnExhwas higher for the brick
specimen than for the granite one but the opposite was seen for
TnExh. In the examined range of relative (RH:7–88%) and absolute
(AH:1–24 g m
3
) humidities the radon and thoron exhalation rate
increased and then above a certain level decreased or reached a
plateau. The plottedfits of the polynomial model to RnExhand
TnExhwith theR
2
parameter as 0.80 (RnExhbrick), 0.71 (RnExh
granite) and 0.82 (TnExhbrick) and 0.84 (TnExhgranite).
Obtained results were compared with other radon and thoron
exhalation measurement results. Since experimental conditions
were different among studies, with the main differences being the
volume of the accumulation chamber, measurement method and
measured parameters, the features of the variation were analyzed.
It was concluded that the present trend of changes was consistent
with other results (Cothern and Smith, 1987; Stranden et al., 1984).