Light pollution is the introduction of artificial light into the night sky. Artificial lighting is the primary cause of sky glow, obscuring the stars and creating perpetual twilight. Light pollution contributes to light trespass issues on public and private properties. Today, 80% of the US population cannot see the Milky Way.
Low Pressure Sodium (LPS) fixtures were an excellent choice for cities that require Dark Sky compliant lighting as well as astronomical observatories and environmentally sensitive areas. However, LPS fixtures have become obsolete and replacement parts are expensive and difficult to obtain.
Most LED luminaires are not Dark Sky compliant.
White LED’s produce a significant amount of blue light. Blue light scatters in the atmosphere, obscuring the view of stars from the ground and contributing to light pollution and sky glow. When compared to existing HPS and LPS fixtures, most LED street lights increase light pollution and sky glow anywhere from 170% to nearly 500%. Externally mounted light shields offer minimal resolution for light pollution and light trespass issues.