In an urban environment, air is strongly polluted by nitrogenous oxides (NOx) and volatile organic compounds (VOCs) produced by intensive human activity, notably transport. In living areas, these pollutants are produced by domestic combustion devices such as gas heaters, electric ovens, building materials and by the infiltration of outdoor pollution. This study deals with the degradation of NO and BTEX (benzene, toluene, ethylbenzene, xylenes (p-/m-/o-xylene)) present in the air by means of a photocatalytic oxidation process based on TiO2 nanoparticles incorporated in a polymer-matrix-based coating. The experimental set-up consisted of a flow type reactor adapted from the ISO 22197 standard. Various parameters influencing the photocatalytic efficiency were studied: the coating composition, the substrate nature, the initial concentration of pollutant, the polluted air flow rate and humidity. NO2 in the gas phase, and nitrate ions adsorbed on the photocatalytic surface were detected as final products. Compared to glass, the use of mortar as the substrate enhanced the photocatalytic performance of coatings by reducing the generation of gaseous NO2 as a by-product. The degradation of BTEX can only be observed under low gas flow rates. Considering the different compounds in the VOC mixture, photocatalytic oxidation rate increased in the following order: benzene, toluene, ethylbenzene, xylene. The reactivity order of these compounds is consistent with the rate constants for the reaction with hydroxyl radical (OH).