Active botanical biofiltration of air pollutants using Australian native plants

Abstract

Air pollutants are of public concern due to their adverse health effects. Biological air filters have shown great promise for the bioremediation of air pollutants. Different plant species have previously been shown to significantly influence pollutant removal capacities, although the number of species tested to date is small. The aims of this paper were to determine the pollutant removal capacity of different Australian native species for their effect on active biowall particulate matter, volatile organic compounds and carbon dioxide removal, and to compare removal rates with previously tested ornamental species. The single-pass removal efficiency for PM and VOCs of native planted biofilters was determined with a flow-through chamber. CO2 removal was tested by a static chamber pull down study. The results indicated that the native species were not effective for CO2 removal likely due to their high light level requirements in conjunction with substrate respiration. Additionally, the native species had lower PM removal efficiencies compared to ornamental species, with this potentially being due to the ornamental species possessing advantageous leaf traits for increased PM accumulation. Lastly, the native species were found to have similar benzene removal efficiencies to ornamental species. As such, whilst the native species showed a capacity to phytoremediate air pollutants, ornamental species have a comparatively greater capacity to do so and are more appropriate for air filtration purposes in indoor circumstances. However, as Australian native plants have structural and metabolic adaptations that enhance their ability to tolerate harsh environments, they may find use in botanical biofilters in situations where common ornamental plants may be suitable, especially in the outdoor environment.