The impact of HVAC filter on indoor air quality in
terms of ozone removal and carbonyls generation
Chi-Chi Lin* and Hsuan-Yu Chen
Department of Civil and Environmental Engineering, National University of Kaohsiung, No.700, Kaohsiung University Rd., Nan-Tzu Dist., Kaohsiung City, Taiwan, ROC
ABSTRACT
In order to find out ozone removal rates and corresponding carbonyls generated by ozone reaction with HVAC filters in various building, i.e., shopping mall, school, and office
building, one study was conducted in a small-scale environmental 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 samples in tubes were injected into gas chromatography (GC) and analyzed by mass spectrometry (MS). By examining dust properties such as organic carbon proportion and specific surface area on dusts adsorbed on filters along with ozone removal rates and carbonyls generation rate, the relationship among dust properties, ozone removal rates, and carbonyls generation were found. The ozone removal efficiencies on the filters in mall, school (A), school (B), and office building range from 46% to 56%, 11% to 14%, 91 to 92%, and 8% to 9%, respectively. The concentrations of carbonyls generated by ozone reactions on the filters in mall, school(A), school (B), and office 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. The results indicate a
well-defined positive correlation between ozone removal efficiency and carbonyls generation on filters, as well as a positive correlation among the amount of organic carbon on filters, ozone removal efficiency and carbonyls generations. However, no significant correlation was
found between surface areas of dusts on filters and ozone removal efficiency or carbonyls generation.
