Abstract: Air filtration apparatuses, systems and methods for nitrous oxide and volatile organic compound (VOC) removal and non-VOC particle removal enable the removal of particulates, nitrous oxide-containing compounds, and volatile organic compounds from large volume enclosed environments. Systems incorporate HEPA filtration upstream from UV LED-assisted photo reaction chamber comprising a plurality of baffles having air flow-through airflow spaces are spaced apart along a duct, with a porous and permeable nitrous oxide-adsorbing filter oriented downstream from the UV-assisted photo reaction chamber further filtering the airflow in the system to remove nitrous oxide-containing compounds.