The Biofiltration Ability of Asparagus densiflorus to Remove Sulfur Dioxide from the Indoor Atmosphere

Sulfur dioxide is an inorganic compound (IC) and air pollutant that causes health risks in humans at concentrations as small as 6 ppm. The buildup of sulfur dioxide in enclosed indoor spaces is therefore a concern to human health, especially since the average person spends 90% of his/her time indoors. This study focused on decreasing a sulfur dioxide concentration in a cost-effective and simple way—by using botanical biofiltration, or the uptake of pollutants by plants. Research in biofiltration has focused mostly on the remediation of volatile organic compounds (VOCs) and which plant species are most proficient at VOC uptake. However, research has also shown that species that remediate VOCs efficiently also have the potential for superior IC remediation. Asparagus densiflorus, which has a large capacity for VOC uptake, has been researched very little concerning ICs, and has not yet been tested for the uptake of sulfur dioxide. Therefore, this study sought to fill that research gap by testing the remediation of Asparagus densiflorus of sulfur dioxide in an airtight container. This was accomplished by measuring the amount of sulfur dioxide removed during 3 hours in an airtight container in the presence of an Asparagus densiflorus plant divided by the amount of sulfur dioxide in the absence of the plant. This result was considered the fraction of sulfur dioxide remediated by the plant. The final results in this experiment, although showing significant fraction of sulfur dioxide removal, were too variable to be conclusive about the amount of sulfur dioxide removed from an enclosed atmosphere and therefore of the biofiltration ability of A. densiflorus. Nonetheless, further research using a different research design is recommended to investigate whether A. densiflorus is more efficient than other plants at removing sulfur dioxide from the atmosphere and therefore could be used in larger-scale biofilters that must utilize space effectively