From Simulation to Space: Impacts of Green Coverage Ratio and Spaciousness on Occupant Well-being in a Semi-outdoor Atrium

¹ Kajima Corporation, Kajima Technical Research Institute, 1820036 Tokyo, Japan
² Kajima Corporation, Kajima Technical Research Institute Singapore, 489490, Singapore

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Our previous study explored how green coverage ratio and spaciousness influence self-reported performance and mood using a virtual reality (VR) head-mounted display. A semi-outdoor atrium was built in Singapore in the tropical climate to reflect the optimal conditions identified through VR experiments. This study aims to evaluate the effects of green coverage ratio and spaciousness on occupants' self-reported performance and mood in the actual built environment, and to validate the prediction model developed from the VR study. A field survey was conducted in five locations within the atrium, each representing different combinations of high/low green coverage ratio and spaciousness from March to April 2024. Thirty-five occupants participated by completing a questionnaire after a 2-minute break during their working hours. We asked for their environmental satisfaction, moods, and self-reported performance such as work efficiency, mental fatigue and recovery. Temperature, relative humidity, illuminance, and noise level were measured during the experiment. The results showed that participants in high greenery spaces demonstrated higher visual comfort, concentration and more positive moods, as well as reduced mental fatigue, compared with the baseline workplace environment. Interestingly, even though air temperature was approximately 5 °C higher and noise levels were 6-8 dBA higher than in the workplace, occupants in the high greenery spaces reported feeling more comfortable both thermally and acoustically. The analysis further indicated that green coverage ratio tended to have a particularly strong effect on relaxed mood, while spaciousness tended to influence self-reported concentration and work efficiency. These findings support the notion that well-designed semi-outdoor environments with high greenery coverage ratio and sufficient spaciousness can promote psychological restoration and enhance workplace performance through strategies that optimize break intervals.