FAQ - Dmoz/Society/Issues/Environment/Light_Pollution

Archive-name:dmoz.org/Society/Issues/Environment/Light_Pollution
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Last-modified:2004-04-23 14:51:43
URL:http://dmoz.org/Society/Issues/Environment/Light_Pollution/faq.html
Category:Society/Issues/Environment/Light_Pollution

Table of Contents

1  What is Light Pollution?
2  Who does it affect?
3  What are the detrimental effects?
4  What forms of light pollution are there?
5  Which lights are least polluting?
6  What is a lighting code or ordinance?
7  What is a darksky preserve?

1   Q: What is Light Pollution?
A: Light Pollution (also called obtrusive lighting) is not the opposite of heavy pollution :-D but pollution caused by the increasing use of urban, and now rural, outdoor lighting which has deemed many countries practically unsuitable for observations using astronomical telescopes.
by joeblakesley at 2001-06-15 13:28:19
2   Q: Who does it affect?
A: Everyone - we can all be kept awake by nearby floodlights and neighbours' security lights.

Astronomers - stars become invisible to the naked eye and any normal astronomical observation becomes impossible.

Drivers - cars can veer off the road when drivers cannot see due to or are distracted by glare.

Pilots - Lights can confuse pilots of boats and aeroplanes which can and has caused serious accidents.

Animals - nocturnal animals can be blinded, crash land or hurt themselves where bright lights are used.

Plants - some plants can be stunted/die if subjected to 24 hour lighting.

by joeblakesley at 2001-11-16 12:24:04
3   Q: What are the detrimental effects?
A: The detrimental effects of light pollution are many and varied. As well as the astronomical effects: pollution costs a lot for the polluters, and uses up valuable energy and fossil fuels; the creative beauty of the night sky is lost for future generations; plants are stunted or die, and are confused by the bright lights; insects are killed by the heat; birds and other (especially nocturnal) animals are blinded and/or confused by the bright lights so that they crash-land or become hurt (reductions in nocturnal animal populations, especially moth and bird populations, is often attributed to artificial lighting); aeroplanes and boats can and have crash-landed, hit rocks or lost their way due to the pilots? confusion; driver?s are dazzled and can veer off the road; people cannot see in the vicinity of lights especially where shadows are created; blind people are aggravated by the brightness; traditionally tranquil parts of the world like the Peak District are no longer free of man-made obstructions to the landscape as nearby towns and cities are aglow; regular exposure can be detrimental to eyesight, and cause depression, insomnia and headaches in some people; false alarms are sometimes made by people believing bright lights are fires, and there is no significant reduction in crime where security lights are used (in some cases, crime, is made easier, not harder, by security lights as the experience of some police has shown).
by joeblakesley at 2001-06-22 23:30:32
4   Q: What forms of light pollution are there?
A: There are 3 recognised forms: glare, skyglow and light trespass. Glare is the temporarily blinding effect of viewing a bright light on a dark background (effects drivers and pedestrians). Skyglow is the bright orange glow seen over many cities. It is caused by many lights collectively and mainly effects astronomers. Light trespass is the shining of a neighbour's light onto your property causing sleepless nights or inability to see properly on your property (effects mainly residents).
by joeblakesley at 2001-05-04 21:36:15
5   Q: Which lights are least polluting?
A: Broadly speaking, full cut-off lighting (lighting from which no light is emitted above he horizontal) is the best. Also no light should be directed where it is not needed.

Generally, in order of increasing capital cost and decreasing long-term cost and pollution, the light bulbs are as follows:
Incandescent (normal domestic),
Fluorescent,
Mercury vapour (MV),
Metal halide (MH),
High-pressure sodium (HPS),
Low-Pressure sodium (LPS).

If you are considering purchasing a light and need more information, many of the lighting manufacturers include light-pollution information on their sites, or , for more impartial advice, go to the International Darksky Association website or the Lighting Code Handbook webpage.

by joeblakesley at 2001-05-04 22:14:02
6   Q: What is a lighting code or ordinance?
A: A local code defining the allowed levels of lighting often set by local council planning departments or similar local bodies. Please see the description, sites and subcategories of Society: Issues: Environment: Light Pollution: Regulation. For further information also see the lighting code handbook, or contact your local council or light-pollution campaign group to find out if one is being implemented.
by tschild at 2004-04-23 14:51:43
7   Q: What is a darksky preserve?
A: An area, similar to a national nature reserve, which is designated by the goverment as worthy of special protection against light pollution due to its dark skyglow-free skies.
by joeblakesley at 2001-06-11 23:41:12

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