Simulated and measured calibration of PADC detectors is given for cylindrical diffusion chambers employed in environmental radon measurements. The method is based on determining the minimum alpha energy (Emin), average critical angle (<0c>), and fraction of 218Po atoms; the volume of the chamber f1), are compared to commercially available devices. Radon concentration for exposed detectors is obtained from induced track densities and the well-established calibration coefficient for NRPB monitor. Calibration coefficient of a PADC detector in a cylindrical diffusion chamber of any size is determined under the same chemical etching conditions and track analysis methodology. In this study the results of numerical examples and comparisons between experimental calibration coefficients and simulation purpose made code. Results show that the developed method is applicable when uncertainties of 10% are acceptable.