Evaluation of volatile organic compound removal efficiency in indoor air using single plant and mixed plant botanical filter systems

Ensuring indoor air quality (IAQ) is increasingly important in sustainable building design. Active botanical filters represent a promising sustainable technology for air purification. This study systematically compared the removal efficiency of contaminants such as acetone, toluene and α-pinene in a vertical green wall planted with Syngonium podophyllum , with that of a similar green wall planted with a combination of Epipremnum aureum and Syngonium podophyllum . The impact of internal air recirculation and liquid nutrient flow, and the role of plants, on pollutant removal was assessed in both green walls. The botanical biofilters demonstrated remarkable removal efficiencies, ranging from 70% to 100%, depending on the air and nutrient recirculation flowrates. The microbial community within the biofilter showed progressive evolution from Cupriavidus , Pseudomonas , and Bradyrhizobium , to more versatile Mycobacterium and Asinibacterium genera. The efficacy of the system was validated through complementary batch test in bottles, which demonstrated the ability of microorganisms grown in the biofilter to efficiently degrade volatile organic compounds. The results underscore the potential of active botanical filters as a scalable solution for improving IAQ in built environments. These green walls can be integrated into HVAC systems to reduce reliance on conventional mechanical filtration and chemical treatments, lowering operating costs and carbon footprint.