Code for calculating the vertical distribution of radon isotopes and their progeny in the atmosphere Original Research Article

A one-dimensional time-dependent eddy-transport model is developed for estimating the vertical distributions of 222Rn, 220Rn and their progeny, activity ratios of progeny to parent, unattached fraction and equilibrium factor in the Earthʹs lower atmosphere. The model takes into account radioactive decay, attachment to aerosol particles, recoil, dry deposition, rainout and washout processes. The turbulent diffusion equations are solved numerically using a backward time centred space differencing scheme after choosing a dimensionless logarithmic scale for the vertical coordinate.