What is light pollution?

Light pollution is 'any adverse effect of man-made light including sky glow, glare, light trespass, light clutter, decreased visibility at night, and energy waste'. (International Dark-Sky Association)

"Light pollution is the inefficient, uneconomical use of light, use that sends light wastefully toward the sky or light that provides so much glare you can’t see anything else."

Why is it light pollution bad?

It wastes huge amounts of money/energy. In the UK alone, it is estimated that street lighting throws £100m+ of unnecessary light into the night sky every year due to the poor design of many streetlight fittings. The proliferation of badly designed and overpowered domestic lighting is also adding to the growing waste. Popular, but usually innapropriate, 500w and 300w halogen 'insecurity' floodlights use 10x the power needed, and provide poorly directed and dazzling light as well.

Generating all of this wasted power creates huge quantities of CO2 and other greenhouse gases.

It's Unsafe
Contrary to popular belief, bright dazzling lighting does not make it easier to see at night. The human eye is more comfortable and efficient in lower, more even light levels, so lower wattage and better light direction is more important than simple, wasteful brightness, and provides safer light levels to navigate or see intruders by.

But what about Security?
It's a myth that brighter lighting automatically provides better security. There is at least as much evidence to suggest it has the opposite effect. Certainly many people may feel more secure at night around very bright lights, but every day we hear of muggings, rapes, violence and vandalism happening directly under bright street lighting, or even in broad daylight. Criminals need light to see their victims by, and will often avoid darker areas entirely.

Surveys have repeatedly shown that a light on inside a home or office is a far more effective deterrent than an outdoor one. If you're out, fit a time controller to switch lights on and off at programmed times to suggest that someone is home.

Disturbed Sleep and Health Problems
Many people regularly have their sleep disturbed by over-bright streetlighting, neighbours floodlights, or by sky glow. This interferes with the body’s rhythms, and causes sluggishness, poor concentration, depression and irritability. As well as seriously affecting health, the knock-on effect is lost work efficiency, accidents and expensive healthcare. Our bodies evolved to sleep in natural darkness, and our basic right to health is being undermined by carelessless and profligacy.

Recent research also suggests strong links between light pollution and cancer, particularly breast cancer.

Sky Glow
Looking around you at the night sky, it seems that wherever you live these days, in city or the country, it is blighted by an unpleasant orange or yellow glow caused by artficial lights wasting light and energy into the sky.

Many astronomers are very concerned about the impact that this has on science, as increasingly they are unable to study the night sky due to the stars being obscured by this pollution. In the UK alone, it is estimated that 60% of school children can no longer see most of the stars in the night sky due to this wasteful phenomenon - a great tragedy as astronomy is on most schools curriculums, and few pupils can now study the 'real' stars, having to use a computer simulation instead.

But it's not just a tragedy for astronomers. For many ages Mankind has admired and wondered at the broad sparkling vista of the 'dark sacred night'.

Human history and religion is coloured by this wonder, and it is our loss, and that of our children, if we blot this out through wastefulness, selfishness, and apathy.

How can we reduce light pollution?

Though much light pollution is created by huge streetlighting schemes, office buildings left lit all night, and industrial estate 'insecurity' floodlights, we can all play our part in helping to curb it. Here are a few things you can do to 'bring back the night'.

• Use low wattage and power-saving bulbs (preferably 'CFL' compact fluorescent). Do you really need that 300w halogen? A well directed 'full cut-off' 60w light could be better, cheaper to run, and less polluting?
• Buy better outdoor light fittings: such as the Smartflood or Glarebuster, which are 'full cut-off' designs, preventing unnecessary light shining upwards.
• Switch them off! The best kind of light is one that's switched off when it's not needed. It saves you money, and can help you and everyone else enjoy the beauty of the night sky again. Even better if you can convince your employer or company to do the same.
• Look around you. If you see unnecessary, dazzling or wasteful light blighting your town, ask the owner, politely, if they can switch it off or replace it with a better, more efficient fitting. If they say no, move on. Others may be more receptive.

Remember - the right amount of light, directed where needed.