Soininen and colleagues thoroughly investigated the repercussions of having green walls in Finnish offices. They found that “air-circulating green walls may induce beneficial changes in a human microbiome. . . . The green walls (size 2 m × 1 m × 0.3 m) used in this study . . . circulate indoor air. They first absorb the indoor air through the plant roots and soilless substrate, then automated fans circulate the air back to the room. When the indoor air passes through the green wall, volatile organic compounds (VOC) are efficiently removed via biofiltration by microbes, plants and the growing medium. . . . Each green wall contains three plant taxa (heartleaf philodendron (Philodendron scandens), dragon tree (Dracaena sp.) and bird’s nest fern (Asplenium antiquum) growing altogether in 63 units. Each unit consists of two to four plant individuals. . . . Spending time in green wall rooms seems to be related to increasing abundance of health-supporting skin microbiota within a relatively short time period of two weeks.” Previous research has identified positive cognitive and emotional effects of in-office green walls (and plants generally).
L. Soininen, M. Roslund, N. Nurminen, R. Puhakka, O. Laitinen, H. Hyoty, A. Sinkkonen, and ADELE Research Group. 2022. “Indoor Green Wall Affects Health-Associated Commensal Skin Microbiota and Enhances Immune Regulation: A Randomized Trial Among Urban Office Workers.” Scientific Reports, vol. 12, 6518, https://doi.org/10.1038/s41598-022-10432-4