The invention relates to a system and method to sanitize a fluid while it is moving through a distribution system. The invention provides significant improvements in efficacy and reductions in cost over previous approaches. At least one embodiment of the invention is applicable to commercial, industrial, military, government, public and private facilities that employ forced-air ventilation systems, especially those with comparatively dense human occupancy. The invention has particular utility in hospitals, health care facilities, manufacturing facilities, offices, apartments and dormitories, military housing, afford and schools, as well as on ships, commercial airliners and in public and private transportation. At least one embodiment of the invention may be used to deliver UV-C to a specific surgical site to sanitize the site to prevent future infection.
