Sources of Light Pollution
Once we start to understand the causes and the sources of light pollution, we will be able to do what it takes to reduce and minimize its effect.
Many people see light pollution as a one-dimensional issue, however it is much more complicated and varied than most people think. There are many varieties and sources of light pollution, such as excess light that disturbs natural darkness; insufficient light, like when human-made illumination drowns out natural light, or when our structures create unnatural shade; and changes to the non-visible light spectrum (infrared or radio waves).
These are the five most destructive types of light pollution:
- Over Illumination: This type of light pollution is generally the result of misuse or neglect of light sources. Over illumination is easy to spot; street lights that don’t have their schedules properly adjusted for the season or daylight savings time, or interior lights that have been left on accidentally.
- Light Trespass: This term refers to undesired light shining on someone’s property. Examples of this are exterior lights that are set up improperly or neon signs that spill light into a residential area. Light trespass is incredibly annoying for those affected, and in some areas is even considered to be a crime.
- Light Clutter: Irresponsibly dense arrangement of lighting sources creates light clutter. Street lights or commercial signs can wash out an area, interfering with night visions and disturbing the circadian rhythms of nocturnal animals.
- Glare: Produced when reflected light disturbs vision, glare is both uncomfortable and dangerous. We have all experienced glare while driving when the sun reflects off a wet road or the windows of nearby buildings. Glare creates obvious danger for motorists and can disrupt our daily lives at home or at work.
- Sky Glow: This form of light pollution is only appreciable from a distance. Perhaps you’ve noticed, when approaching a big city from the road or by air, a dome of light that covers the city. That light is the overflow from residential, commercial, and industrial illumination being scattered out into all directions. Sky glow disrupts the natural cycles of people and animals that live within the city, but the negative effects can extend far outside the city limits. Sky glow even effects the ability of planes to navigate at night.