Source: David Fernández-Barba, Dep. d’Astronomia i Meteorologia, Universitat de Barcelona, SPAIN
Light trespass is light falling where it is not intended or needed. Light trespass can be spill light from a streetlight or floodlight that enters a window and illuminates an indoor area causing problems, like sleep deprivation.
Source: David Fernández-Barba, Dep. d’Astronomia i Meteorologia, Universitat de Barcelona, SPAIN