Study On The Chemical/Microorranic Contaminant And Passive Humidity Control Of Indoor Air

Indoor air quality significantly influenced people's health and comfortable due to the facts that people spend most of their time in indoor environment. The significance of indoor air quality was iterated by SARS outbreak in 2003 and expecting possible avian flu outbreak. This thesis is focused on how to create a safe and comfortable indoor environment for people. The mechanism of VOC emission, the control of indoor air pollutants including VOC, bio aerosols and the control of influenced factor relative humidity were investigated in this study from three aspects as followed:Firstly, the physical properties of VOC emission from construction or decoration materials were studied in the present thesis. We developed a model to predict VOC concentration considering the influences of temperature, ventilation rate, thickness of the materials etc. The model was validated by the measured data from literatures. The model was employed to study the influences of temperature, ventilation rate and thickness of materials to VOC emission and conduction inside the materials. The effective range of bake-out method was obtained from the results. It was found from theory that the method integrated of bake-out and ventilation was an efficient way to remove VOC both from indoor air and materials.Secondly, this thesis developed a concept to integrate high voltage, filter and photo catalysis into a multifunctional air cleaner for removing airborne bio-aerosols, VOC pollutants. An air cleaner was designed according to the concept and was tested in an enclosed chamber of simulated HVAC system. Results show that the average total efficiency of this air cleaner can achieve to as high as 86.2%. It can decompose VOC, remove particles and cut off the transmitted route of airborne infectious diseases. This air cleaner is hoped to creat for safe environment for people during disease epidemic such as SARS and the expecting possible avian flu.Thirdly, this thesis studied the passive dehumidify with low energy consume, which is to control the growth of pathogens as humidity is one of important factors to influence the growth of bacteria or virus. Humidity also influences the efficiency of photo catalysis. So the suitable range of humidity of air can inhibit the growth of bacteria or virus, increase the efficiency of photo catalysis equipments and improve the thermal comfortable for people. The material was tested in a small environment chamber and thermostatic tested room with different conditions. Results show that the RH of the indoor air can be adjusted to be 45%-60% by the compositing passive material.