Efficacy of Indoor Plants for the Removal of Single and Mixed Volatile Organic Pollutants and Physiological Effects of the Volatiles on the Plants

Abstract

<jats:p>Foliage plants of <jats:italic>Hedera helix</jats:italic> L. (english ivy), <jats:italic>Spathiphyllum wallisii</jats:italic> Regal (peace lily), <jats:italic>Syngonium podophyllum</jats:italic> Schott. (nephthytis), and <jats:italic>Cissus rhombifolia</jats:italic> Vahl. (grape ivy) were evaluated for their ability to remove two indoor volatile organic air pollutants, benzene and toluene. Removal was monitored when the aerial portion of plants was exposed singly to 1 μL·L<jats:sup>-1</jats:sup> or to 0.5 μL·L<jats:sup>-1</jats:sup> of each gas in a closed environment over 6-hour periods during the day and the night. Selected physiological processes were assessed before and immediately after treatment to determine the effect of the gases on the plants. The effectiveness of plants in the removal of air pollutant(s) varied with species, time of day, and whether the gases were present singly or as a mixture. When exposed to a single gas, <jats:italic>S. wallisii, S. podophyllum,</jats:italic> and <jats:italic>H. helix</jats:italic> displayed higher removal efficiencies (ng·m<jats:sup>-3</jats:sup>·h<jats:sup>-1</jats:sup>·cm<jats:sup>-2</jats:sup> leaf area) of either gas than <jats:italic>C. rhombifolia</jats:italic> during the day. The efficiency of removal changed when both gases were present; <jats:italic>H. helix</jats:italic> was substantially more effective in the removal of either benzene or toluene than the other species, with the removal of toluene more than double that of benzene. When exposed singly, the removal of both compounds was generally higher during the day than during the night for all species; however, when present simultaneously, <jats:italic>H. helix</jats:italic> removal efficiency during the night was similar to the day indicating that stomatal diffusion for english ivy was not a major factor. The results indicated an interaction between gases in uptake by the plant, the presence of different avenues for uptake, and the response of a single gas was not necessarily indicative of the response when other gases are present. Changes in the rates of photosynthesis, stomatal conductance, and transpiration before and after exposure indicated that the volatiles adversely affected the plants and the effects were not consistent across species and gases. Deleterious effects of volatile pollutants on indoor plants may be critical in their efficacy in improving indoor air quality and warrant further study.</jats:p>

Effects of Indoor Plants on the Physical Environment with Respect to Distance and Green Coverage Ratio

“…Because mechanical ventilation and air-conditioning generally consume energy, research should focus on energy-free methods of regulating indoor air quality and microclimate [19]. Studies conducted since 1989 have reported that indoor plants can significantly reduce urban air pollution [20][21][22][23][24][25][26]. Nevertheless, little research has conducted experiments in a daily living environment to examine the effects of indoor plants on air quality, temperature, and humidity.…”

Current State of Indoor Air Phytoremediation Using Potted Plants and Green Walls

“…By considering the potential of plants to remove VOCs, there are some studies on benzene removal. Studies showed that plants have high resistance against toxic pollutants [144][145][146]. Recently, Sriprapat et al [8] exhibited the experimental data for eight species of plant, including Sansevieria trifasciata, Euphorbia milii, Epipremnum aureum, Syngonium podophyllum, Hedera helix, Chlorophytum comosum, Dracaena sanderiana, and Clitoria ternatea, for removing benzene in air and water pollutants.…”

Fundamentals of Ornamental Plants in Removing Benzene in Indoor Air

“…Furthermore, in order to accurately assess the VOC removal efficiency of plants, the traditional method of the test chamber has been improved [10], and a great deal of research has been conducted. Most of these research has focused on treating benzene in indoor air by C3 plants and has found that they have potential to improve indoor air quality [11][12][13][14][15]. However, few studies have focused on the benzene removal efficiency of crassulacean acid metabolism (CAM) plants [16], which is a type of effective phytoremediation plant and a common ornamental plant in indoor environments.…”