The photocatalytic conversion of organic model pollutants (acetone, acetaldehyde, and isopropanol) in a novel Photo-CREC-Air unit is considered. This photocatalytic unit features: (1) external near-UV lamps placed in parabolic reflectors, (2) a basket supporting the irradiated glass mesh holding TiO2 loadings to achieve high photoconversion rates, and (3) a fluid flow pattern securing high gas velocities in the near-mesh region. Given the high quantum efficiencies observed in Photo-CREC-Air and, as a result, the high prospects,for this novel design, rate equations and associated mechanistic formulations are investigated. With this goal, a Langinuir-Hinshelwood model, involving a one-site model pollutant mechanism, is considered. The associated kinetic parameters with the related statistical indicators art, established, using least-square nonlinear regression. It is found that this model is adequate,for describing the photodegradation of acetone oil both Degussa P25 and Hombikat UV-100. It is also observed that the same type of reaction rate model is less adequate for the photodegradation of acetaldehyde and isopropanol, in particular, for predicting the formation of carbon dioxide. (C) 2004 American Institute of Chemical Engineers AIChE J, 50: 1017-1024, 2004