SIR Economics Investigation Abstract
LIGHT POLLUTION: WASTED LIGHT AND MONEY
Presenter:
Martha Malin, Illinois Mathematics and Science Academy, 1500 West Sullivan Road, Aurora, IL, 60506
Advisor:
Ms. Laura Nickerson, Illinois Mathematics and Science Academy, 1500 West Sullivan Road, Aurora, IL, 60506
Abstract:
The goal of this inquiry was to find a light system for the city of Chicago that reduces light pollution and is cost effective. With the city’s current lighting situation, the night sky is 91.6 times brighter than the natural night sky. Chicago uses high-pressure sodium light in partially shielded light fixtures, which causes two-thirds of the light to shine at the sky or onto another beam of light. This costs the city approximately $7.26 million a year. The city is wasting close to two million dollars a year in excess light. If the city used fully shielded fixtures and low-pressure sodium lights, the annual cost of street lighting would be $5.31 million a year. The change in lighting would not decrease the lights’ mean lumens, but the night sky would only be twenty-five times as bright as the natural dark sky. This design would not only save the city of Chicago money and increase the effectiveness of existing lighting systems, but would provide an opportunity for budding city-bound astronomers to wonder at the night skies.