Outdoor Lighting and Dark Skies

This website provides a sampling of local dark sky ordinances and other resources related to dark skies.

Excessive night lighting is now recognized as a form of pollution with the potential for causing damage to some trees. However, effects of supplemental lighting on trees are complex. Understanding tree response depends on the type of lamps used and the spectrum of radiation emitted, the intensity of that radiation, and the role of light in certain biological processes. [Cheney, William R. "Does Night Lighting Harm Trees?" Purdue University, Department of Forestry and Natural Resources]

This website contains information on how to control, reduce, and regulate light pollution and conserve energy usage, including lighting ordinance information.

POLC maintains a set of model lighting ordinances on its website that have evolved over time to incorporate the most recent and most effective ordinance language. The site also contains enacted lighting ordinances from across the Commonwealth as well as helpful information on initiating an ordinance and links to other relevant resources.

This atlas shows that more than 80% of the world and more than 99% of the U.S. and European populations live under light-polluted skies. The Milky Way is hidden from more than one-third of humanity, including 60% of Europeans and nearly 80% of North Americans. Moreover, 23% of the world’s land surfaces between 75°N and 60°S, 88% of Europe, and almost half of the United States experience light-polluted nights.