Ability of artificial and live houseplants to capture indoor particulate matter

Two artificial and three live houseplants were assessed for their abilities to capture particulate matter smaller than 2.5 µm (PM_2.5) generated by burning an incense stick. The test plants included polyester Boston fern, polyethylene Dieffenbachia, Golden Pothos (Epipremnum aureum), Painted nettle (Plectranthus scutellarioides) and Rainbow tree (Dracaena cincta Bak. ‘Tricolor’). Each plant was tested one at a time in a closed 8-m³ chamber, and the PM_2.5 concentrations were continuously measured for 24 h. A loss rate constant for PM_2.5 due to deposition onto leaf surface was determined by fitting measured concentrations to a mass balance model using nonlinear regression. The PM_2.5 loss rates for the artificial Boston fern correlated well with its total leaf surface areas at the significant level of 0.5. All studied plants had PM_2.5 loss rates ranging from 0.05 to 0.08 h⁻¹ under the testing condition of similar total leaf surface areas, while a PM_2.5 loss rate due to deposition onto the chamber surfaces was 0.03 h⁻¹. Stereo microscope leaf images revealed the particle accumulation mostly on the midribs and veins rather than the flat blades, while the woven polyester fabric of the artificial plant acts as a filter for collecting the coarse particles.