Natural plants have long been recognized as nature's air purifier, drawing 25% of human-made CO2 emissions from the atmosphere annually. Plants can absorb and catabolize almost any airborne pollutants, although this phytoremediation capacity has been poorly applied indoors. “Indoor plants are typically selected on the basis of their aesthetic features rather than physiological requirements reflecting their capacity to remove air pollutants” (Cell Press Reviews 2018). Despite their simplistic experimental approach, pioneer studies conducted by NASA during the 1980s and more recently by the University of Technology Sydney in 2009 successfully demonstrated that plants are capable of removing airborne pollutants (in particular, CO2 and VOCs). The capacity of plant leaves to exchange gases, and thus to take up any pollutants from indoor air, is limited by physical processes controlling opening and closing of microscopic leaf pores, namely stomata. The following video explains, how this works.
Nevertheless, the VOC-removing ability of potted plants in real indoor environments (rather than laboratory conditions) remains a challenge and a subject of debate. While some researchers concluded that potted plants do not clean the indoor-air fast enough to have an effect on the air quality of their home or office, other studies have demonstrated how leveraging soil and plant microbiome can potentially improve the cleaning capacity of potted plants by 200 times. Evidence suggests that plant-based biofilteration help breakdown VOCs three times faster than the natural decay rate, offering potted plants as a promising alternative biofilteration technology with biophilic productivity and well-being benefits.