This work presents an experimental study on the clogging behaviour, filtration efficiency and airflow resistance of various filter media under controlled aerosol loading and relative humidity (RH). The goal was to assess how RH affects the time to reach a target differential pressure drop in the test rig and to relate this to fractional efficiency, mass deposition and air resistance performance. Four filter media (A, B, C and D) were tested under constant and cyclic RH conditions. At constant RH, clogging time increased with RH: for A and B, raising RH to 60% significantly delayed reaching the final pressure drop. In contrast, C achieved the final pressure drop more quickly, even at 60%.