Abstract: An air treatment system includes a pathogen treatment chamber that is configured with one or more channel assemblies such that air passing therethrough is treated with ultraviolet (UV) light. A channel assembly includes multiple parallel channels configured between the opposed ends of the channel assembly. One end of each channel is configured with an ultraviolet (UV) light source exhibiting a first wavelength, while the remaining end of each channel is configured with an ultraviolet (UV) light source exhibiting a second wavelength. A removable light source module including the UV light sources exhibiting the first wavelength spans one of the opposed ends of the channels, while another removable UV light source module including the UV light sources exhibiting the second wavelength spans the remaining opposed ends of the channels.