Thursday, November 17, 2005

Light Pollution

by Sarah Flannery (Class of '05)

Astronomers and stargazers worldwide face the threat they will no long be able to see their beloved night sky because of light pollution. Light pollution is defined as the “glow of light we see at night above cities and towns,” according to the Ontario Hydro Leaflet on Light Pollution. (Ontario Hydro is a progressive electrical utility for Ontario, Canada. It’s caused by poorly designed outdoor lights, such as street and parking lights. The light spills to the side and glows upwards, making the stars less visible. If lights were designed to minimize upward light leakage, light pollution would not be a problem. Light pollution consists of five main components: glare, light trespass, clutter, energy waste, and urban sky glow. Glare blinds us and harms visibility. Light trespass is when somebody’s outdoor lights spill out, or “trespass” onto other people’s property. Finally, urban sky glow destroys our view of the universe. Light pollution has the potential to blot out the night sky in just a few generations from now if we do not do something. Fortunately, there are many steps that even the average person can take to stop light pollution from taking the beauty of the night sky away from us.

The average person can help by investing in quality, efficient lighting for their homes. The light from inside buildings is one of the six major causes of light pollution. Good lighting is well-shielded, so that the light uses just enough light but not too much, and uses lighting sources that are energy efficient. Other things that will help are turning off flights when they are not needed, and using night lighting only when it is really necessary. Since most of the problem of light pollution lie outdoors, local governments and businesses have a big responsibility to reduce light pollution, because they can do the most to help reduce it.

Five out of the six major causes of light pollution can be prevented by businesses or governments. These five causes are: public, street lighting, the lighting from cars, the floodlighting of advertising signs and buildings, the floodlighting of sports stadiums, and security floodlighting. To start with, outdoor light should be regulated, so that the glow does not go to an extreme. If noise pollution can be regulated, then light pollution should be regulated as well. Outdoor fixtures should be shielded just like indoor fixtures are, to prevent spillage of light into the night sky. Billboards and signs should be lighted from the top down instead of the bottom up. When installing outdoor lighting , some things to keep in mind are to make the illumination even, and to only use light where and when it is needed. These are all simple solutions to a massive problem.

All info obtained from information sheets on

Links to this post:

Create a Link

<< Home