Abstract: An air treatment unit having a frame and a source of UV light, with the frame having an air guidance assembly. Air within a primary treatment volume is guided by the frame to move radially outwardly from the primary treatment volume through a dispersion angle. Air within the primary treatment volume is exposed to UV light rays from the UV light source. The air treatment unit is changeable between: a) a first state wherein a predetermined part of a volume of space within which the air treatment unit resides is strategically blocked from direct exposure to UV light rays generated by the UV light source; and b) a second state wherein at least a portion of the predetermined part of the volume of space is directly exposed to UV light rays from the UV light source.

Abstract: An air treatment unit has: a frame; a source of UV light; and an air moving assembly that causes air within a space to be directed into a volume that has UV light rays therein from the source of UV light. The air treatment unit has a primary treatment volume. The frame has an air guidance assembly that extends substantially fully around an axis extending through the primary treatment volume and defines at least one elongate opening through which disinfected air is communicated from the primary treatment volume in a pattern substantially fully around the axis to outside of the frame and the air treatment unit in a radial direction within a region of the space outside of the primary treatment volume.