²²²Radon is often used to parameterise atmospheric transport in the lower troposphere. It can be measured via its decay products, which are bound to aerosol. Air sampling through long tubing, which sometimes cannot be avoided at tall tower sites, may then cause severe aerosol and corresponding radon daughter activity loss. We have quantified this loss for 8.2 mm ID Decabon tubing used at European stations and provide a length-dependent correction function for this experimental setting.