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This study aims to investigate the correlation of the photocatalytic oxidation effect of decomposing organic matter and inactivating bacteria using two different TiO2 materials: a Degussa P25 powder film and a commercial TiO2 thin film. The destructed organic matter was formaldehyde and the test bacterium was E. coli (JM 109 strain). The decomposition tests and the bactericidal tests were carried out in a plate reactor and on the TiO2 surface, respectively. Observations indicate that there exists an apparent correlation between the two photocatalytic processes of decomposing formaldehyde and inactivating E. coli. However, it is essential to distinguish the exact driver for microbe inactivation, in which both UV light irradiation and reactive oxygen species reaction are directfactors of disinfection, and for organic matter, in which only reactive oxygen species reaction contributes to degradation. Observations from this study would make it possible to use analogy as a potential method to evaluate the antimicrobial effect based on the organic compound degradation effect, whereby the latter is much easier to measure quantitatively.

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Ultraviolet (UV) light irradiation, including the type of light source, light intensity, and irradiation dosage, directly affects the photocatalytic reaction rate and energy consumption. In this study, we investigated the photocatalysis effect of decomposing organic matter and inactivation bacteria and fungi under various conditions of UV sources (UVA and UVC) and light intensities (from 0.01 to 10 W/m2). The effect of light intensity was evaluated by photocatalytic reaction rate and UV dosage defined as a product of light intensity and irradiation time necessary to achieve a certain reduction. The results confirmed the positive effect of increased light intensity on photocatalytic reactions and suggested that within the light intensity range applied in this study low light intensity with long exposure time has higher light utilization efficiency compared to that of high light intensity with short exposure time. A conception for selection of the appropriate light intensity and dosage for effective degradation of pollutants, while saving energy, was provided.

A post-occupancy study was carried out to investigate the thermal environment in a high-standard office building certified by China Three-star Green Building Label. The study included a subjective evaluation of the indoor environment quality and work performance. A total of 182 office workers responded to the questionnaire survey based on the Building Use Studies (BUS) Occupant Survey and Reporting Method. Objective measurements of the thermal environment (temperature and relative humidity) under mechanically and naturally ventilated conditions were also carried out in the building. Although the thermal environment satisfied the majority of respondents, 12% and 20% reported dissatisfaction with summer and winter temperatures, respectively. The complaint on summer temperature was mainly from those working close to the chilled air outlets of the air-conditioners. The perception of cold winter temperatures revealed the potential shortcomings of sustainable building design in humid subtropical climates, where natural ventilation and passive cooling would predominate in the sustainable design while cold air in winter would tend to be neglected. The purpose of this study was to investigate the reasons why green buildings succeeded or failed to meet occupants' perception and this could have an implication in the design decisions for green building practice.