Light and Glare (LG)
This factor refers to man‐made lighting (street lights, airfield lighting,
building lights) and glare (direct or reflected light) that disrupts vision. Light
sources from commercial, industrial, recreational, and residential uses at
night can cause excessive glare and illumination, impacting the use of
military night vision devices and air operations. Conversely, high intensity
light sources generated from a military area (such as ramp lighting) may
have a negative impact on the adjacent community.
Key Terms
Glare. The presence of excessively bright light, such as direct or reflected
sunlight, or artificial light, such as sport field and stadium lights at night.
Glare reduces visibility and can completely impair vision when very intense.
Light Pollution. This type of pollution is created by the artificial brightening
of sky caused by development, including street lights and other man‐made
sources. This has a disruptive effect on the natural cycles and inhibits the
observation of stars and planets and can render night vision devices
ineffective.
Night Vision Device. An optical instrument that allows images to be
produced in varying levels of light approaching darkness. These devices are
often used by military and law enforcement agencies.
Technical Background
In measuring light pollution, the proximity to a community has a significant
effect on the amount of light pollution that saturates the sky. Proximity
twice as close to a community makes its sky glow appear approximately six
times brighter.
Sky glow from communities typically diminishes in the later hours of the
night, when businesses close and some lights are turned off. It follows that,
as development continues to progress outward from a community, the area
Background Report
and amount of light pollution can increase. Increased light pollution can
cause an increase in the amount of sky glow, and ultimately create
compatibility issues with military missions.
The impacts of the use of outdoor lighting on the dark skies are primarily
determined by two principal factors – the amount of developed land
(density) and the distance of the developed land from the installation. The
relationship between density and distance is best demonstrated using an
estimate of urban sky