A sequential air purification system (100) is disclosed. The system (100) comprises: a primary purification unit including at least one filter selected from a pre-filter (102) and a minimum-efficiency reporting value (MERV) filter (104) a secondary purification unit including at least one stage of at least one photo-catalytic oxidation (PCO) filter (106, 110) coated with a catalyst and a dopant provided in operative communication with one or more ultra-violet lamps (108), the PCO filter (106, 110) substantially encompassing the lamp (108) a tertiary purification unit including at least one filter selected from a high-efficiency particulate air (HEPA) filter (112) and an activated carbon filter (114) and a fan (116) for directing the purified air flow.
