Photocatalytic lasures (semi-transparent coatings) intended for building materials were formulated using TiO2 nanoparticles incorporated in a polymer-matrix-based coating. Their performances in terms of air purification were assessed on a VOC (volatile organic compounds) mixture representative of atmospheric pollution (benzene, toluene, ethylbenzene and xylenes or BTEX).The possible toxicity of the formulated coatings was also investigated by analysing the VOC possibly released by the lasures themselves. The experimental set-up used in the air purification experiments consisted of a flow type reactor adapted from the ISO 22197-3 standard. The results show that humidity has a strong influence on the degradation rates of BTEX; an optimal humidity level could be identified only at high initial pollutant concentration. The emission experiments were conducted in static mode using solid phase microextraction. Esters were detected in the dark and under UV illumination but no contribution of photocatalysis to emission was identified.