What is Light Pollution?

LIght pollution is the sky glow created by artificial lighting, in particular, bad lighting fixtures, which causes light to be scattered up into the sky instead of down on the ground where the light is needed.  Light pollution should be considered the same as noise pollution, except that light operates at a different wavelength.  Imagine a neighbor setting up a 1000 watt light and shining it in your bedroom window.  That would be just as bad as the same neighbor turning on their stereo full volume.

This is a satellite photograph of the United States taken at night.  It shows the spread of sky glow (light pollution) from our urban areas.  If we don't start acting now, the beauty of the night sky will be gone forever.

So what!!!??  Why should you care about light pollution? 

• As sky glow increases, the night sky gets brighter and brighter until the only the brightest stars are visible.  Ten years ago, it was possible to see the Milky Way from backyards only a few miles from the GA 400 & GA 53 corridor.  Now, the faint star cloud is no longer visible due to the expanding sky glow from the area.  Several local observatories are loosing their dark sky sites due to the encroaching sky glow.
• It is a huge waste of energy!  It is estimated that 30-40% of all light is wasted by scattering it other than where it is needed.  If we can cut the overall brightness by 50%, the energy reduction is staggering.  Remember, Georgia Power is grabbing our land because of the demand.  If we reduce demand, power companies couldn't justify their actions.
• It just isn't safe.  Driving into many of the Dawson County businesses at night leaves drivers temporarily blinded due to unshielded fixtures and excessively bright parking lots.  The elderly are especially suseptible to this temporary blindness.  Everyone has experienced the pain of driving south on GA 400 at night and reaching GA 53.  Squinting is a common reaction. 
• Wildlife moves away from areas that are too brightly lit.  As a Dawson County resident, wildlife watching is a favorite evening passtime.  With the addition of streetlights in our community, the wildlife has disappeared.  Studies have shown that plant and animal life is altered dramatically by the removal of a dark (night) cycle.  Sea turtles and birds are prime examples of the dangers to the animal community.
• It isn't healthy.  Studies show that darkness is absolutely required for Melatonin, a key hormone produced for sleep. 

What Causes Light Pollution?

The cause of Light Pollution is simple... BAD LIGHT FIXTURES!!

This is a good illustration of the good and bad fixtures. 

There are only 2 rules to prevent light pollution:

1. Use only FULL-CUTOFF fixtures.  That means that when you view a light fixture from the side, you should not see the light source or the lens.  The Dawson County GA 400 Development guidelines require full-cutoff fixtures. Unfortunately, businesses are not following the guidelines.
2. Lights MUST point 90 degrees down.  Any angle put on a light fixture causes light tresspass and glare.  The following illustrates this:

This shows how aiming a light can affect the amount of light pollution produced from the same fixture.  The Dawson County guidelines require cutoff light shields on any light that is not pointed 90 degrees down.  Again, businesses are not complying.	This shows the 3 different types of light fixtures.