LIGHT POLLUTION

http://www.rasc.ca/im/lpa/cinzano_canada.jpg

This is the same location near Toronto on two different nights:one during a black out and the other during a “normal” night.

http://www.skykeepers.org/astro-lp.html

Types of Light pollution

●Glare: Blinding or irritating bright light when you look at it. Example: Bright lights reflecting off your windshield that obstructs one's view and hides hazards.

●Light Trespass: Light going where it is not wanted or needed. Example: A streetlight shining in your bedroom window.

●Sky Glow: Illumination of the night sky from poorly directed or unshielded light. Example: Orange glow seen over cities at night

●http://home.cogeco.ca/~richardastro2/

What causes light pollution?●Any exterior light source that permits light

to go upwards or where it is not needed. There are several different aspects of this..○ Unnecessary - Lights that have no useful purpose

or are lit when not needed. ○ Excessive - Lights that are too numerous or simply

too bright. ○ Badly designed - Lights that are not properly

shielded or have no shielding at all. ○ Badly installed - Lights that are poorly directed or

situated.

Why should we care? Health●Light pollution has been linked to many

human health issues:○depression,○sleep deprivation, ○near sightedness, ○high blood pressure, ○breast cancer.

Why should we care? Safety

Many streetlights create a glare that actually make it more difficult for motorists to see in the distance. This is especially dangerous for pedestrians.

http://calgary.rasc.ca/lp/frame.html

Why should we care? Money● The cost of all that light is millions of dollars a year:

most of it from taxpayers for streetlights● http://www.britastro.org/dark-skies/calculators.html

● The City of Calgary alone saved 2 miilion dollars a year by using better lightinghttp://content.calgary.ca/CCA/City+Hall/Business+Units/Roads/Streetlights/EnviroSmart+Streetlight+Retrofit/EnviroSmart+Streetlight+Retrofit.htm

● Producing the electricity creates more CO2 emissions that adds to global warming.

○ In Alberta, a single 100-watt incandescent porch light left on all night shines 1/2 of its light into space and causes 390 kg of carbon-dioxide pollution each year. That's enough to fill 44,340 twenty cm (8") party balloons! From one light bulb! http://calgary.rasc.ca/lp/frame.html

Why should we care: Wildlife

● Light pollution also affects animals by interfering with their natural sleeping, migration and even breeding behaviours.

● Experts believe that up to 100,000,000 birds are killed every year in North America alone.

● http://www.flap.org/

● http://www.flap.org/

Why should we care: Wildlife

● “The effect is so powerful that scientists speak of songbirds and seabirds being "captured" by searchlights on land or by the light from gas flares on marine oil platforms, circling and circling in the thousands until they drop. Migrating at night, birds are apt to collide with brightly lit tall buildings; immature birds on their first journey suffer the most.

● Endangered sea turtles become confused by light on the land and head inland instead of the ocean when they hatch”

● http://ngm.nationalgeographic.com/2008/11/light-pollution/klinkenborg-text/2

In the natural world, light areas represent the passageways.

Lit windows fool birds into colliding with them.

http://calgary.rasc.ca/lp/frame.html

In the natural world, light areas represent the passageways.

Lit windows fool birds into colliding with them.

http://calgary.rasc.ca/lp/frame.html

Solutions: Government

http://www.rasc.ca/lpa/darksky.shtml

Solutions:Government

● Establish Dark Sky Preserves○ A DSP is an area in which no artificial lighting is visible and

active measures are in place to educate and promote the reduction of light pollution to the public and nearby municipalities.

○ http://www.rasc.ca/lpa/darksky.shtml

● Pass laws that require all new exterior lights to have reflective shields

● Pass “light trespass” laws similar to physical trespass laws.● Prohibit unnecessary outdoor lighting after 11 pm or

entirely: such as flag poles, monuments, landscape lighting etc.

● A flat-lens cobra luminaire, which is a full-cutoff fixture, may be effective in reducing light pollution. It ensures that light is only directed below the horizontal, which means less light is wasted through directing it outwards and upwards.● http://en.wikipedia.

org/wiki/Light_pollution

Solutions:Individual

●There are many ways you can make a difference.●Using low-energy bulbs, ●Switching lights off when they are not needed. ●Using timers on outside lights●Covering lights so that they are reflected back

down on the ground where they are needed

Sites used

● http://www.delscope.demon.co.uk/information/lightpollution.htm#difference

● http://home.cogeco.ca/~richardastro2/● http://content.calgary.

ca/CCA/City+Hall/Business+Units/Roads/Streetlights/EnviroSmart+Streetlight+Retrofit/EnviroSmart+Streetlight+Retrofit.htm

● http://en.wikipedia.org/wiki/Light_pollution● http://www.rasc.ca/lpa/darksky.shtml● http://ngm.nationalgeographic.com/2008/11/light-

pollution/klinkenborg-text/2● http://environment.about.com/od/pollution/a/light_pollution.

htm● http://calgary.rasc.ca/lp/frame.html

BIBLIOGRAPHY

● Hasselden, D. (2008,July,20). Light Pollution Questions and Answers. Retrieved November 11, 2008, from Light Pollution Questions and Answers Web site:http://www.delscope.demon.co.uk/information/lightpollution.htm#difference

● (2008). Stop light pollution. Retrieved November 11, 2008, from RASC Sarnia Centre Web site: http://home.cogeco.ca/~richardastro2/

● (2008,November,8). Light Pollution. Retrieved November 11, 2008, from Wikipedia Web site: http://en.wikipedia.org/wiki/Light_pollution

● Grey, Dennis (2008,October,28). Light pollution abatement program. Retrieved November 11, 2008, from The Royal Astronomy Society of Canada Web site: http://www.rasc.ca/lpa/

● Klinkenborg, Verlyn (2008,November). Light pollution . Retrieved November 11, 2008, from National Geographic Web site: http://ngm.nationalgeographic.com/2008/11/light-pollution/klinkenborg-text/1

● West, Larry (2008). Light pollution raises risks of breast cancer. Retrieved November 14, 2008, from About.com Web site: http://environment.about.com/od/pollution/a/light_pollution.htm

● (2008). Light pollution pages of the Calgary Centre of the RASC. Retrieved November 14, 2008, from RASC Calgary Centre Web site: http://www.britastro.org/dark-skies/calculators.html

● (2007,December.04). Astrnomical light pollution. Retrieved November 14, 2008, from Skykeepers.org Web site: http://www.skykeepers.org/astro-lp.html