Experimental investigation of active living wall systems for enhancing indoor air quality

Indoor environmental quality directly affects occupant health and comfort, with air pollution and odor perception representing two important determinants. This study systematically evaluated the combined effects of an active living wall system (ALWS) on indoor air quality and odor perception. Four cases were tested: Case 1 (soil), Case 2 (soil + filtration), Case 3 (plant + soil) and Case 4 (plant + soil + filtration). Variations in CO 2 concentration and particulate matter (PM) was monitored. Results showed that under 24 hours supplementary lighting, CO 2 concentration remained within 200 ppm-450 ppm, demonstrating carbon regulation and air purification capacity of the ALWS. In PM experiment, Case 4 exhibited the best performance, reducing PM2.5 below 50 µg/m 3 within approximately 517 min and PM10 below 100 µg/m 3 in 419 min, indicating efficient particle adsorption and deposition. After calculation, the removal efficiencies of Case 4 for PM2.5 and PM10 were determined to be 41.61 µg/m 3 ˙ s and 83.6 µg/m 3 ˙ s, respectively. In Case 4, uncovering the chamber increased the mean air-freshness score from 0.63 to 1.38 and the odor-comfort score from 0.31 to 1.21, while decreasing the odor-intensity score from 1.52 to 0.83. Overall, the ALWS not only improved physical air quality but also enhances psychological comfort through visual-olfactory interaction, providing a holistic strategy for healthy and biophilic indoor environments.