Studies on Removal of Formaldehyde by Indoor Plants
Date Issued
2010
Date
2010
Author(s)
U, Kuan-Hong
Abstract
Formaldehyde is one of the common indoor volatile organic compounds and has been classified as a human carcinogen. Plants can reduce formaldehyde concentration as shown in previous reports. In this study, we determined removal capacity of formaldehyde by twenty species/cultivars of indoor plants, four species of cut flowers, and five species of cut leaves. Plant materials were exposed to formaldehyde (1 ± 0.01 μL•L-1) in airtight chambers (0.128 m3) and the amount of formaldehyde removal was assessed under various light intensities, CO2 concentrations, and long term formaldehyde exposure conditions.
Twenty indoor plant species/cultivars were found to be effective in reducing formaldehyde concentration, which decreased with time. Potted plants of Dendranthema ×grandiflorum (Ramat.) Kitam. ‘Jin-Shan’ , Nephrolepis exaltata (L.) Schott ‘Bostoniensis’ and Spathiphyllum floribundum (Linden & André) N. E. Br. ‘Palas’ had the highest formaldehyde absorption rates of 0.78 μL•L-1, 0.64 μL•L-1 and 0.56 μL•L-1 per pot, respectively, during the first one hour exposure. Cyclamen persicum Mill. ‘Bright Red Compact’, D. ×grandiflorum (Ramat.) Kitam. ‘Jin-Shan’, and Dracaena fragrans (L.) Ker Gawl. ‘Massangeana’ had highest removal efficiencies, as calculated on a leaf area basis, with the shortest time to reduce 50% of the initial concentration (T50%) at 21 ± 2, 22 ± 3, and 27 ± 8 min, respectively.
The cut flowers and cut leaves could remove formaldehyde. Among the cut flowers tested, chrysanthemum had the highest formaldehyde absorption, and could remove 0.60 μL•L-1 formaldehyde concentration in the chambers during the 8 h experiment. Formaldehyde removal rate decreased when leaves were detached. Formaldehyde absorption by cut flowers increased with increasing relative humidity in the chamber. Among the cut leaves tested, Aspidistra elatior Blume ‘Variegata’ and Fatsia japonica (Thunb.) Decne. & Planch. had the highest removal efficiencies of 0.22 μg and 0.23 μg per cm2 leaf area during the 4 h exposure. Linear relationships existed between formaldehyde removal and net photosynthesis rate (r = 0.72***) or stomatal conductance (r = 0.72***), respectively, for five species of cut leaves.
Seven Araceae plants could reduce small amounts of formaldehyde in dark conditions. Formaldehyde absorption, net photosynthetic rate, and stomatal conductance increased in S. floribundum (Linden & André) N. E. Br. ‘Palas’ as light intensity increased from 0 μmol•m-2•s-1 to 120 μmol•m-2•s-1 PPF. The net photosynthetic rate of other six Araceae plants increased linearly with increasing light intensity, while saturated formaldehyde absorption occurred at 80 μmol•m-2•s-1 to 120 μmol•m-2•s-1 PPF.
When plants of S. floribundum (Linden & André) N. E. Br. ‘Palas’ were placed in the chambers, carbon dioxide concentration in the chambers increased in the dark and decreased in the light conditions. High CO2 concentration at 1134.8 μL•L-1 reduced formaldehyde absorption of plants, while more formaldehyde was reduced by plants with increasing light intensity from 80 μmol•m-2•s-1 to 160 μmol•m-2•s-1 PPF.
Formaldehyde removal efficiency of Dieffenbachia maculata (Lodd. et al.) G. Don ‘Camilla’ was assessed by shoot, whole plant, root zone, and root zone with sterilization. The formaldehyde removal by shoot was lower than by whole plant. Exposure to formaldehyde did not alter net photosynthetic rate, SPAD-502 value and Fv/Fm in the recently fully developed leaves in shoot or whole plant during the seven successive days. Root zone could remove 60% initial formaldehyde concentration in the chambers each day for successive seven days. Formaldehyde absorption of root zone after sterilization increased with time. Regardless of root zone sterilization or not, no significant difference was observed in formaldehyde absorption on day 7.
Subjects
Indoor air quality
phytoremediation system
sick building syndrome
volatile organic compounds
SDGs
Type
thesis
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