Novel insights into indoor air purification capability of microalgae: characterization using multiple air quality parameters and comparison with common methods.

Indoor air purification received more attention recently. In this study, the effects of six common indoor ornamental plants (Epripremnum aureum, Chlorphytum comosum, Aloe vera, Sedum sediforme, Cereus cv. Fairy Castle, and Sedum adolphii) and three kinds of microalgae (Chlorella sp. HQ, Scenedesmus sp. LX1, and C. vulgaris) on the removal of four types of air pollutants (particulate matters less than 2.5 (PM2.5) and 10 μm (PM10) in size, formaldehyde (HCHO) and total volatile organic compounds (VOCS)) in test chamber compared with common physical purification methods (high efficiency particulate air filter and nano activated carbon absorption) were investigated. Their effects on oxygen, carbon dioxide, and relative humidity were also evaluated. The results showed that microalgae, especially C. vulgaris, was more suitable for removing PM2.5 and PM10, and the removal rates were 55.42 ± 25.77% and 45.76 ± 5.32%, respectively. The removal rates of HCHO and VOCs by all three kings of microalgae could reach 100%. Part of ornamental plants took a longer time to achieve 100% removal of HCHO and VOCs. Physical methods were weaker than ornamental plants and microalgae in terms of increased relative humidity and O2 content. In general, microalgae, especially C. vulgaris could purify indoor air pollutants more efficiently. The above studies provided data and theoretical support for the purification of indoor air pollutants by microalgae.