"Indoor air quality (IAQ) is becoming a major health concern as modern buildings are being increasingly sealed from the outdoors; allowing pollutants such as VOCs to accumulate indoors. Biofiltration has been proposed as an alternative to ventilation for maintaining IAQ. Indoor air is very different than waste gas streams treated in conventional biofilters. An indoor air biofilter must handle very large volumes of air containing a large consortium of VOCs present at trace concentrations. Ecologically complex, plant-based biofilters have been designed to treat VOC-contaminated indoor air. Prototypes have been shown to improve IAQ through the elimination of target VOCs. "