陳宣宇 就臭氧去除與醛酮類化合物生成來探討中央空調濾網對室內空氣品質影響之研究 The impact of HVAC filter on indoor air quality in terms of ozone removal and carbonyls
generation 摘要 據美國環保署指出，現代人們長時間處於室內空間之中，加上台灣地區氣候炎熱， 使得中央空調系統普遍存在於各式建築物中，這也更突顯出中央空調系統對室內空 氣品質之影響。 本研究主要將針對賣場、學校、辦公大樓等主要不同建築型態建築物中之中央空 調系統進行深入的探討，分析各地點建築物中央空調系統濾網對臭氧的去除效率及 醛酮類化合物之生成量，並分析濾網上灰塵有機碳組成、比表面積、官能基型態， 藉以對比濾網上灰塵特性與臭氧去除及醛酮類化合物生成之關聯性。本實驗主要利 用小型環境模擬箱，並輔以臭氧產生機、氣霧式加濕器、氣冷式空氣壓縮乾燥機及 加熱器以達實驗參數條件，並利用空氣採樣幫浦進行採樣，接續以氣相層析質譜儀 進行醛酮類化合物定量分析。研究結果發現，各地點濾網對臭氧去除效率依序為學 校活性碳濾網(92%-91%)、賣場(56%-46%)、學校(14%-11%)、辦公大樓(9%-8%)。而 在醛酮類化合物生成量中，其總濃度高低依序為學校活性碳濾網 (89.5μg/m3-83.7μg/m3)、賣場(26.9μg/m3-17.2μg/m3)、學校(3.9μg/m3-2.2μg/m3)、 辦公大樓(1.7μg/m3-1.4μg/m3)。由相關實驗結果可以得知中央空調濾網對臭氧之去 除效率與其所產生之醛酮類化合物有明顯的關聯性；而此結果亦與濾網上灰塵之有 機碳組成比例高低成正相關趨勢，顯示出濾網上灰塵有機碳組成比例對濾網的臭氧 去除效率與醛酮類化合物生成量有明顯相關性。但上述相關實驗結果對比濾網上灰 塵之比表面積特性分析數據時，相關性卻不明顯。 由本實驗研究結果可以發現中央空調濾網在通入臭氧時會去除一部分臭氧，這看 上去很好，但同時卻會產生出一定量的有害醛酮類化合物（如甲醛），結果可能嚴 重威脅到室內空氣品質及室內的人體健康，因此，後續對臭氧在濾網上的相關反應 模式以及臭氧去除量和醛酮類產物生成量之間的關聯性模式的相關研究非常重要。 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.
