An original photocatalytic reactor for the treatment of polluted air is designed. The titanium dioxide is Supported on various supports that consist in photopolymers and are built using the stereolithography technique and placed in a glass tube illuminated from the outside, while the air containing the pollutant to be removed flows through the glass tube and the photocatalyst support. It is shown that the gas-solid mass transfer plays a role only at the very smallest gas velocities investigated. The global depollution kinetics are then determined for the different geometrical forms of the photocatalyst support and the efficiency of the forms compared. (C) 2009 Elsevier B.V. All rights reserved.