Physiological and psychological effects of exposure to different types and numbers of biophilic vegetable walls in small spaces

With the increase of indoor isolation in modern society and the growing development of manned deep-space and deep-sea exploration, the mental health issues of people in small spaces are becoming increasingly prominent. In recent years, the biophilic design that introduces plants into the indoor environment has become one of the solutions to these problems, among which the green wall is favored because of its high spatial efficiency. However, there is a lack of systematic research on the greenery dose and greenery layout of green walls in relation to the health of indoor people. In this study, a self-report + electrophysiological analysis method, combined with virtual reality technology, was used to explore the physiological and psychological effects of different types and numbers of vegetable walls on people in small spaces. The results showed that the vegetable wall with a low greenery dose may not be sufficient to elicit significant psychological responses, while when the greenery dose of a single vegetable wall was too high, the physiological relaxation effect would decrease. The regulation effect of the vegetable wall was also related to the greenery layout, and the half-sized vegetable wall was better than the full-sized one when with the same medium greenery dose. Moreover, negative emotions tended to decrease as the number of vegetable walls increased. People experienced lower subjective negative emotions when exposed to the biophilic environment with three vegetable walls. This research provided an important reference for determining the optimal type and number of vegetable walls to regulate people's mood.