常見室內植物對苯之吸收及反應

Abstract

揮發性有機物質為室內重要的空氣汙染物，而苯是為致癌物，也是最常見的揮發性有機物質之一。本研究欲以苯為對象，篩選出對苯吸收能力較佳的室內植物，並了解不同環境因素，如光照及二氧化碳濃度等對苯吸收速率之影響。 本研究取十七種常見室內植物，在小型熏氣箱中以25ppm 之苯進行熏氣，測量各種植物在500 Lux 弱光下之沈降速率。結果顯示，綠帝王蔓綠絨與綠精靈合果芋之吸收效率最高，沈降速率分別為0.14mm/sec 與0.16mm/sec。若以科別為分類，則以天南星科、鐵角蕨科等科對苯有較高的吸收速率。 比較十七種植物在5000 Lux 強光下與500 Lux 弱光下之沈降速率差異，結果顯示強光可使十七種植物的氣孔導度增高，且在十七種中有十種植物在強光下的沈降速率比弱光下高，表示多數植物在強光下吸收污染較多。而其中以黃金心葉蔓綠絨、紅邊椒草及綠帝王蔓綠絨之吸收速率為最高，沈降速率分別為0.14mm/sec、0.14mm/sec 與0.12mm/sec。若以科別為分類，則在強光下以胡椒科、天南星科等科對苯有較高的吸收速率。 另在500 Lux 與5000 Lux 兩種光照強度下，分別測試300∼400ppm、600∼700ppm 兩種二氧化碳濃度下八種植物吸收苯之沈降速率，結果顯示，在低濃度的二氧化碳環境下，強光可使部分植物對苯的沈降速率提升，但在高濃度的二氧化碳下，強光會使大部分植物對苯的沈降速率顯著提升。而不論在強光或弱光下，高濃度的二氧化碳皆會降低植物對苯之沈降速率。

Volatile organic compounds(VOC) are major indoor air pollutants, especially in urban areas. Benzene is one of the VOCs that can be found everywhere, and is a carcinogen. The purpose of this research, therefore, is to screen the plants with higher absorption rate of benzene. The effects of light intensities and carbon dioxide concentrations on the benzene uptake by indoor plants are also studied. Seventeen common indoor plants were exposed to 25 ppm of benzene 500 Lux light intensity in a 52-L fumigation chamber. Results show that Philodendron cv. Wend-imbe and Syngonium podophyllum cv. Pixie have the highest uptake rate of benzene, with deposition velocities as 0.14mm/sec and 0.16mm/sec, respectively. In terms of plant classification the Araceae family and Aspleniaceae family show the higher uptake to benzene. When these 17 plants were exposed to 25 ppm of benzene under strong light of 5000 Lux and weak light of 500 Lux, deposition velocities of 10 plants among them were raised due to higher light intensity. Results also show stomatal conductance of these 17 plants were increased by higher light intensity. Under high light, Philodendron cv. Golden pride, Peperomia clusiifolia, and Philodendron cv. Wend-imbe have the highest deposition velocity, as 0.14mm/sec, 0.14mm/sec, and 0.12mm/sec, respectively. In terms of plant classification, the Piperaceae family and the Araceae family show the higher uptake of benzene. Two levels of carbon dioxide as 300~400ppm and 600~700ppm, were applied to 8 plants during exposure to benzene under strong or weak light intensity. Results show that at level of 300~400ppm, deposition velocities of benzene by some plants were increased by higher light intensity, while at high CO2 level of 600~700ppm, deposition velocities of benzene by most plants were significantly increased by strong light. Under weak or strong light, however, the doubling of CO2 significantly decrease the deposition velocity of benzene by all 8 plants.