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Top 5 Light Pollution Misconceptions

1. Light at night prevents crime.
2. More light improves visibility.
3. You can get good illumination by "throwing" light from HERE to OVER THERE
4. Light pollution is not really pollution because it goes away if you turn off the lights.
5. Light pollution is only a problem for astronomers.

The Golden Rules of Good Lighting

• Use fully shielded fixtures and aim lights downward to keep your light on your own property. This will solve most light trespass and glare problems and it will reduce sky glow.

• Turn lights off when not needed (like your parents taught you!). Most exterior building lights, area lights, and illuminated signs can be turned off overnight when very few people are out. This will not affect security and it will save energy.

• Use the right amount of light. Too much light actually reduces your ability to see by making adjacent areas appear dimmer. This can be hazardous. Good lighting uses carefully-aimed, shielded, low intensity lighting to create more uniform illumination. This provides for better illumination that enhances visibility and reduces energy consumption.

The 3 E's of Responsible Nighttime Lighting: Efficiency, Efficiency, Efficiency

Efficient Lamp:
Choose the most efficient bulb type that meets the goals of your application. Sometimes an inefficient incandescent bulb is the best choice if you want relatively low illumination levels and rapid "on" capability as in a residential motion sensor fixture. Don't choose an efficient lamp if it won't properly do the job.

Efficient Fixture:
An efficient bulb is no good if the fixture it is used in allows light to be sprayed everywhere. Full cutoff fixture designs mean that the light is directed where it is needed and none is wasted by creating glare.

Efficient Application:
Think how the light is to be used. All-night security lights have been shown to have minimal effect on crime levels so motion sensor fixtures are a more appropriate choice. Choose the appropriate light output - remember, sometimes less is more; don't overlight, it can create bigger problems than it solves. Creating bright "pools" of light with strong contrasts to unlit areas allows hazards in the shadows to remain undetected. Sometimes the best solution is to use no light at all.

Calgary Roads' Streetlight Retrofit Program is a Win, Win, Win for Calgary.

The City of Calgary is retrofitting more than 40,000 wasteful, semi-cutoff, residential streetlights with full cutoff ones. By using the more efficient design, they are able to use lower wattage lamps to safely illuminate roadways. Calgarians win, win, win:

• City taxpayers will save $2 million in electricity costs per year.

• The lower CO2 emissions and lower light pollution levels are good for the environment.

• Low-glare light fixtures mean that Calgary roadways will be safer for drivers and pedestrians.

See "Light and Traffic Safety" and "Community Retrofits" on our Main Light Pollution Site.

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Can We Do More to Prevent Light Pollution?

Yes! Light pollution is preventable. We can all do our part at home, at work, at play and where we shop.

City of Calgary Bylaws provide a neighbourly code of conduct for its citizens. By implementing an outdoor lighting bylaw for Calgary we can:

1. reduce negative local environmental and human lifestyle impacts,
2. help conserve energy,
3. ensure safe lighting,
4. protect investment in astronomical facilities, and
5. enshrine civic aesthetic guidelines

Thank you for taking the time to visit our summary website.
There are more details and interesting facts on our Main Light Pollution Website.

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Light and Crime Although many people feel that all-night lighting prevents crime, data do not show a strong relationship between lighting and crime rate. Like many police forces across the world, the City of Calgary Police Service has concluded that when and where crimes occur are not related to the amount of darkness available. Calgary crime statistics show that most break-ins occur when a property is unoccupied (homes during the day; businesses at night, despite "security" lights). "Security" lights can create a false sense of security, and poorly designed "security" lights can obscure criminal activity, both of which may ultimately be detrimental to personal safety. "Security" lights do not replace human vigilance. See "Light and Crime" on our Main Site. Back to Introduction Page

Light and Health The body needs dark nights to allow key chemical reactions to take place. Left: Daily variation in prepubertal girls (I-1, I-2) and early pubertal girls (II) of Follicle-Stimulating Hormone (FSH), a key controller of certain processes in puberty (from Mitamura, Yano, Suzuki, Ito, Makita and Okuno, 2000 J Clin Endocrinol Metab Mar;85(3) :1074-80 ). See "Light and Health" on our Main Site. Back to Introduction Page

Light and Animals There are a number of well-documented adverse effects of nighttime lighting on wildlife, including migrating birds colliding with lit structures at night, changes in reproductive capability and behaviour modifications. Some animals shun lit areas while others take advantage of the light to forage or hunt at the expense of other species. Everyone has seen moths clustering around outdoor lights - attracted to the brightness when they should be looking for a mate. Many large shy predators avoid lit areas altogether. See "Light and Animals" on our Main Site. Back to Introduction Page

Light and Greenhouse Gases Because Alberta's electricity is primarily generated by burning coal and natural gas, an all-night 100 Watt porch light is responsible for approximately 390 kg of CO2 emissions in a year. To meet the Kyoto Accord's goals in 2002 simply by conserving electricity, each Albertan would need to turn off the equivalent of 11 such night lights. Choosing the most efficient lamp that properly does the job allows you to minimise electricity use and hence CO2. See "Light and Greenhouse Gases" on our Main Site. Back to Introduction Page

See "Light and Astronomy" on our Main Site.

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