2.2. Calculation
To calculate the exhalation rate,first the data from the RAD7
were read into an external PC-system, and then they were
approximated by the proper equation to derive the exhalation
rate with the units of mBq m
2
s
1
by using a computer code
written in R language (R Core Team, 2013).
The increase of radon activity concentration can be calculated
with the following exponential equation: