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The performances of a laboratory PhotoCatalytic Oxidation (PCO) device were determined using a recirculation closed-loop pilot reactor. The closed-loop system was modeled by associating equations related to two ideal reactors: a perfectly mixed reservoir with a volume of VR = 0.42 m3 and a plug flow system corresponding to the PCO device with a volume of VP = 5.6 × 10−3 m3. The PCO device was composed of a pleated photocatalytic filter (1100 cm2) and two 18-W UVA fluorescent tubes. The Clean Air Delivery Rate (CADR) of the apparatus was measured under different operating conditions. The influence of three operating parameters was investigated: (i) light irradiance I from 0.10 to 2.0 mW·cm−2; (ii) air velocity v from 0.2 to 1.9 m·s−1; and (iii) initial toluene concentration C0 (200, 600, 1000 and 4700 ppbv). The results showed that the conditions needed to apply a first-order decay model to the experimental data (described in Part I) were fulfilled. The CADR values, ranging from 0.35 to 3.95 m3·h−1, were mainly dependent on the light irradiance intensity. A square root influence of the light irradiance was observed. Although the CADR of the PCO device inserted in the closed-loop reactor did not theoretically depend on the flow rate (see Part I), the experimental results did not enable the confirmation of this prediction. The initial concentration was also a parameter influencing the CADR, as well as the toluene degradation rate. The maximum degradation rate rmax ranged from 342 to 4894 ppbv/h. Finally, this study evidenced that a recirculation closed-loop pilot could be used to develop a reliable standard test method to assess the effectiveness of PCO devices.

Combined with material emission, ventilation has a direct impact on volatile organic compound (VOC) concentrations in indoor environments. In this work, the impact of ventilation on various VOC emission rates relative to wood particleboard is assessed experimentally in a 128 L chamber. Ventilation characteristics have been varied (i) between 2.5 and 5.5 h-1 for the air exchange rate and (ii) between 0 and 1.8 m.s-1 for the air velocity in the vicinity of wood particleboards. Based on the results, the air velocity over the surface of the material is found to have no impact on emission of the eight VOCs monitored. However, our experimental work separate out the reduction of VOC concentration by dilution and the potential emission rate increment when air exchange rate is increased. For most VOC, increasing air exchange rate only induces a concentration reduction by dilution. But, formaldehyde exhibits a singular emission behaviour: the decrease in formaldehyde concentration with increasing air exchange rate is limited compared to other VOCs and the formaldehyde emission rate is observed to increase as a function of the air exchange rate. The input of new air thus appears to promote formaldehyde emission from the solid material. Given these results, IAQ prevention strategies have to take into account the specific behaviour of formaldehyde.