Radon exposure is the second-leading environmental cause of lung cancer, therefore finding ways to reduce the radon inhalation dose is a priority objective. Inhalation dose is calculated considering two contributions, the radon gas on the one hand and its progeny on the other. This paper studies the effectiveness of face masks (surgical masks, FFP2 and FFP3) to reduce the contribution of radon descendants that pass into the respiratory tract and thus reduce associated inhalation doses. To analyze the radon filtering potential of these masks, a continuous radon monitor has been used to estimate the radon concentration and the Potential Alpha Energy Concentration with and without facial masks. The data registered by this monitor, together with an error minimization algorithm developed in Matlab®, allow the Equilibrium Equivalent Concentration to be calculated. These results make it possible to compare the inhalation doses received by a person not wearing or wearing different types of masks, obtaining a dose reduction of 64% for surgical masks compared to the study without mask, a reduction of 71% for FFP2 and 72% for FFP3 masks.