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Mung Hwa Yoo, Youn Jung Kwon, Ki-Cheol Son, and Stanley J. Kays

Foliage plants of Hedera helix L. (english ivy), Spathiphyllum wallisii Regal (peace lily), Syngonium podophyllum Schott. (nephthytis), and Cissus rhombifolia 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-1 or to 0.5 μL·L-1 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, S. wallisii, S. podophyllum, and H. helix displayed higher removal efficiencies (ng·m-3·h-1·cm-2 leaf area) of either gas than C. rhombifolia during the day. The efficiency of removal changed when both gases were present; H. helix 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, H. helix 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.

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Sin-Ae Park, A-Young Lee, Hee-Geun Park, Ki-Cheol Son, Dae-Sik Kim, and Wang-Lok Lee

The objective of this study was to investigate the effects of a gardening intervention as a physical activity in women aged over 70 years. Twenty-one women aged over 70 years were recruited from the community in Seoul, South Korea. Eleven subjects at a senior community center participated in a 15-session gardening program (twice a week, average 50 minutes per session) from Sept. to Nov. 2015. The rest of the subjects who were recruited from another senior community center acted as the control group. Blood lipid profiles, blood pressure, inflammation in peripheral-blood mononuclear cells (PBMC), and oxidative stress were assessed by a blood test before and after the 15-session gardening intervention. The results showed that the subjects in the gardening intervention as a low- to moderate-physical activity had a significant improvement in their high-density lipoprotein (HDL) level, systolic and diastolic blood pressures, and the variables related to immunity such as tumor necrosis factor-α (TNF-α) for inflammation in blood and receptor for advanced glycation end products (RAGE) expression for oxidative stress. The results of this study suggested that the 15-session gardening intervention as a low- to moderate-physical activity led to positive effects on the blood lipid profiles, blood pressure, level of inflammatory markers in blood, and oxidative stress of women aged over 70 years.

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Kwang Jin Kim, Mi Jung Kil, Jeong Seob Song, Eun Ha Yoo, Ki-Cheol Son, and Stanley J. Kays

The contribution of aerial plant parts versus the root zone to the removal of volatile formaldehyde by potted Fatsia japonica Decne. & Planch. and Ficus benjamina L. plants was assessed during the day and night. The removal capacity of the entire plant, aerial plant parts, and root zone was determined by exposing the relevant parts to gaseous formaldehyde (2 μL·L−1) in airtight chambers (1.0 m3) constructed of inert materials. The rate of formaldehyde removal was initially rapid but decreased as the internal concentration diminished in the chamber. To compare the removal efficiency between species and plant parts, the time interval required to reach 50% of the initial concentration was determined (96 and 123 min for entire plants of F. japonica and F. benjamina, respectively). In both species, the aerial plant parts reduced the formaldehyde concentration during the day but removed little during the night. However, the root zone eliminated a substantial amount of formaldehyde during the day and night. The ratio of formaldehyde removal by aerial plant parts versus the root zone was similar for both species, at ≈1:1 during the day and 1:11 at night. The effectiveness of the root zone in formaldehyde removal was due primarily to microorganisms and roots (≈90%); only about 10% was due to adsorption by the growing medium. The results indicate that the root zone is a major contributor to the removal of formaldehyde. A better understanding of formaldehyde metabolism by root zone microflora should facilitate maximizing the phytoremediation efficiency of indoor plants.