Evaluation of Indoor Air Quality and Health Related Parameters in Office Buildings with or without Indoor Plants

Abstract

A case study was conducted to evaluate the quality of indoor air and the health-related parameters of indoor occupants with the consideration of indoor-plant placement in the office buildings in Seoul, Korea from October, 2006 to July, 2007. The office buildings with more than seven floors were categorized into two groups. One group was composed of six newly-built buildings established in 2005 to 2006 and the other group was composed of six aged buildings established in 1990 to 1992. An office room on the 3rd floor was chosen as the place with indoor plants and on the 4th floor as the place without indoor plants. The quality of indoor air was estimated using the concentrations of air-borne fine particles including formaldehyde and other volatile organic compounds (VOCs)—benzene, toluene, ethylene, and xylene (BTEX). The physical condition of indoor occupants was evaluated based on certain health-related parameters such as the symptom degree of sick building syndrome (SBS) and the scale of symptom checklist (90) revised (SCL-90-R). The concentration of formaldehyde was decreased not by the individual application of ventilation or indoor-plant placement but by the combined application of the two factors as evidenced by reductions from 80.8 to 66.4 μg·m−3 in the newly-built building and from 23.3 to 18.6 μg·m−3 in the aged building. The concentrations of BTEX varied with indoor conditions. In office rooms with high concentrations of BTEX, these concentrations were obviously reduced by the individual application of ventilation but hardly reduced by the individual application of indoor-plant placement. The indoor occupants of the newly-built buildings perceived little improvement in the symptom degree of SBS by the individual application of ventilation (changing from 19 to 15 points) or indoor-plant placement (changing from 26 to 25). In contrast, the indoor occupants of the aged buildings felt a good improvement in the symptom degree of SBS by the combined application of ventilation and indoor-plant placement, reducing from 23 to 14 points. Observing the mental health of indoor occupants using SCL-90-R, the various results did not show a clear tendency. It could be tentatively postulated that the individual application of ventilation or indoor-plant placement in the office room failed to make sufficient improvement in the mental health of indoor occupants.