In one embodiment, a light emitting device comprises one or more first light sources emitting UV-C light downward to irradiate the environment below the light emitting device (such as air and the floor and other surfaces). In another embodiment, the light emitting device comprises one or more second light sources emitting UV-C light of a different peak wavelength than the first light sources oriented to emit light upward to irradiate the environment above the light emitting device (such as air, the ceiling, and other surfaces). In one embodiment, one or more first light sources and the one or more second light sources emit light at different, independent duty cycles.