Develop a biophilic design filter for enhancing indoor air quality in tropical buildings

Abstract

Rapid densification in built environments has intensified IAQ challenges, underscoring the need for adaptive and sustainable filtration strategies. This study develops a biophilic design filter system for tropical indoor spaces, integrating moss (bryophyte species), coconut coir, and steam-activated coconut shell biochar as a modular green wall system. Material selection prioritized locally available, cost-effective materials with good air permeability for filtration. The proposed filter system was tested in a controlled environment using a comparative approach between experimental (with filter) and control (without filter) setups. 0.5 m x 0.3 m x 0.3m box with two ducting fans was used to make the testing chamber, that utilized as the controlled environment. The key IAQ parameters, including PM₂.₅, PM₁₀, TVOC, CO₂, temperature, and humidity, were continuously monitored over 20 minutes period following pollutant generation. Specific pollutant decay function and linear regression analysis were applied to analyse the effectiveness of the filter system using removal rates and the Clean Air Delivery Rate (CADR). Results demonstrated that particulate removal, with decay constants increasing from 0.03 to 0.26 min⁻¹ for PM₂. ₅ and from 0.00357 to 0.26 min⁻¹ for PM₁₀. TVOC removal showed enhancement of 0.10 to 0.14 min⁻¹, while CO₂ reduction improved slightly (0.03 to 0.06 min⁻¹). This moss biochar integrated filter can be a low cost, waste derived, and scalable nature-based solution for enhancing IAQ in tropical indoor environments.