Phytoremediation as Adaptive Design Strategy to Improve Indoor Air Quality. Experimental Results Relating to the Application of a Vertical Hydroponic Biofilter

This text investigates the potential of phytoremediation as an adaptive design strategy to improve indoor air quality (IAQ). During recent years, interest in IAQ has been increasing as anxiety regarding chemicals has spread to citizens due to the human risk of octylisothiazolinone, chloromethylisothiazolinone, and methylisothiazolinone contained in domestic antibacterial filters and humidifier disinfectants. Among indoor air pollution sources, volatile organic compounds (VOCs) have been identified as first-level carcinogens; VOC management methods are required to maintain a safe indoor environment. As a solution to this problem, phytoremediation is recognized as the safest IAQ improvement method for the public. This study sought to confirm whether active biofiltration, among the active phytoremediation methods, can be applied to large indoor spaces using air conditioning. A novel approach was used to evaluate the air pollutant removal effect by connecting a vegetation biofilter to an air handling unit (AHU). Here, the total air flow rate condition corresponding to the filter criteria of the large air purifier was reproduced using the AHU, and the single-pass removal performance of the biofilter connected to the AHU was analyzed. As a pollutant source, isobutylene at 5000 ppm, which is used for the calibration of a photoionization detection VOC sensor, was tested for 6 h, and an average reduction value of 3826.4 ppbv was recorded. Through three-time repetitive pollutant removal tests, the vegetation biofilter recorded an average 20% single-pass efficiency, indicating significant reductions in air pollution sources. According to the results, the vegetation biofilter developed for the AHU connection conforms with the physical standards of a commercialized air purifier filter. Thus, adequate pollutant reduction performance can be secured using the proposed phytoremediation method.