Efficiency of tropical plants and smart green wall on reduction of fine particulate matters (PM2.5 and PM0.3–1.1) in a closed-system chamber

This study investigates the effectiveness of plant species in reducing ambient fine particulate matter (PM). Among 10 tested species in a closed-system chamber, Spathiphyllum cannifolium achieved the highest PM_2.5 reduction (26 %), followed by Nephrolepis cordifolia (22 %) and Tabernaemontana divaricata (17 %). The superior performance of S. cannifolium is likely attributed to its morphological features, including a grooved leaf surface, large leaf area, and stomata on both leaf sides. A smart green wall combining these 10 plant species was evaluated for its efficiency in reducing PM_2.5 and size-fractionated PMs (PM_0.3–9.0) in a 64-m³ chamber filled with particulate matter generated from forest leaf burning. Initial PM_2.5 concentrations in the chamber were approximately 300 µg/m³ . A room with smart green walls and an empty room (control) were the two situations investigated. The temperature ranged from 26.5°C to 28.5°C, relative humidity from 39.5 % to 40.5 %, and light intensity ranged from 2620 to 2650 lux. The results showed that, PM_2.5 concentrations in empty rooms or controlled condition without smart green walls were reduced from 300 µg/m³ to 121 µg/m³ within one hour. The smart green wall reduced PM_2.5 from 300 µg/m³ to 89 µg/m³ within one hour. In the initial stage of dry leaf burning, the aerosol concentration peaked at nearly 200,000 particles/cm³ , with fine particles (PM_0.3–0.65) accounting for the majority. The Smart Green Wall reduced fine particles by 39–41 % of the total count. While this suggests some potential for PM reduction in micro-scale urban settings, real-world effectiveness would depend on environmental conditions.