Abstract: Embodiments of the present technology are directed to air treatment reactor modules, and associated systems and devices. An exemplary reactor module can include a housing, an ultraviolet (UV) light source disposed within the housing, and a plurality of hollow elongate conduits disposed within the housing and peripheral to the UV light source. The UV light source and individual conduits can extend in a lateral direction perpendicular to the direction of air flow through the reactor module. The conduits can include a plurality of holes and be at least partially coated with a photocatalytic material. The housing can have an inner surface comprising a reflective material that, in operation, reflects UV light emitted from the UV light source.