Development of standardized method for the determination of the degradation of nitric oxide (NO) in the air by photocatalytic materials: Inter-laboratory validation tests

International audienceThe need of a uniform experimental procedure for assessing the performance of photocatalytic inorganic materials contained in building materials led the European Committee for Standardization (CEN/TC386/WG2) to elaborate a Technical Specification (TS).Taking into consideration the importance of the effects which will be of possible variations in the implementation of the reference method, parallel photocatalytic tests according to the TS were performed in the current study. 6 European labs were participated in an inter-laboratory exercise where the experiments had to be done in a special design CEN reactor using LED system. The experimental procedure and conditions were taken from the draft TS and were referred to the average irradiance, inlet NO & NO 2 concentration, T o C and RH inside the reactor, flow and reactor net volume. Identical photocatalytic samples were provided to all participants. The results obtained from the 6 labs showed a variation between 18% and 31% on the photocatalytic NO conversion while the mean value was 26%. The corresponding photocatalytic rate was ranged between 2600 μg/m 2 h and 4100 μg/m 2 h presenting a mean value of 3400 μg/m 2 h. The homogeneity of the lamp and the homogeneity of the deposition of TiO 2 are the main factors impacting the results