Analysis of and control policies for light pollution from advertising signs in Taiwan

Densely installed advertising signs have become a common source of light pollution in Asian countries. Due to mixed land use, there is a question as to whether or not the sign luminance limits set by the CIE are effective in preventing light trespass from these signs. Light trespass from advertising signs was comprehensively analysed by field measurements and software simulations. The results show that, in Taiwan, although the luminances of almost all of the signs are much lower than the limit set by the CIE, they still cause serious light trespass due to their large coverage area, high density distribution and improper installation. From an urban planning point of view, control policies are recommended as models for other countries with similar environmental problems.