| Summary: | 碩士 === 國立高雄大學 === 土木與環境工程學系碩士班 === 99 === The heating, ventilation and air conditioning (HVAC) system is very important for hot and moist areas, especially in Taiwan. According to the report from USEPA, people stay in indoor spaces for most of their time. Therefore, a study of HVAC system impact on indoor air quality is needed.
This study aims to find out ozone removal rates and corresponding carbonyls generation by ozone reaction with HVAC filters in different types of building, i.e.: shopping mall, school, official building, etc. The relationship between dust properties and ozone removal rates along with carbonyls generation could be found by the analyses of organic carbon proportion, specific surface area and types of functional groups on dusts sorbed on filters.
This study was conducted in a small-scale environmental simulation chamber. Ozone generator, mist humidifier, air-cooled dryer and heater were used to generate input ozone-air. An air pump was utilized to sample the air inside the chamber into sampling tubes. Finally, the sample inside sampling tubes were injected into gas chromatography (GC) and analyzed by mass spectrometry (MS).
The result showed that the ozone removal efficiency in mall, school, activated carbon filter of school and official building ranged from 46% to 56%, 11% to 14%, 91 to 92% and 8% to 9%, respectively. The concentration of carbonyls generation in mall, school, activated carbon filter of school and official building are 17.2 to 26.9 μg/m3, 2.2 to 3.9 μg/m3, 83.7 to 89.5 μg/m3 and 1.4 to 1.7 μg/m3, respectively.
In this study, the result shows a significant correlation between ozone removal efficiency and carbonyls generations on filters, and between the composition of organic carbon on filters and ozone removal efficiency and carbonyls generations. However, the results do not show any significant positive correlation between surface areas of dusts and ozone removal efficiency and carbonyls generations.
It is beneficial to remove some part of ozone when ozone passing through HVAC filters. However, there are lots of harmful compounds, carbonyls (such as formaldehyde) produced and emitted into indoor space at the same time. Therefore, the model of ozone reaction with HVAC filters along with carbonyls generation on HVAC filters is very important in future studies.
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