Light Pollution

" noun - excessive brightening of the night sky by street lights and other man-made sources."

The quote above about light pollution is a reference from the AskOxford online dictionary.

Basically, the cause of light pollution is by the inappropriate use of outdoor lighting. This ranges from poorly aimed and overpowered 'security' lighting to unshielded street lighting and any other outdoor lighting which spills light onto surrounding land not intended to be lit and up into the sky. Light pollution has been proven to affect wildlife, cause health problems to affected individuals, is a vast waste of money and energy, adds to pollution increasing greenhouse gas emissions and severely blocks our view of the night sky.

The Earth at night, It's not very hard to see where the populated places are! http://visibleearth.nasa.gov/view_rec.php?vev1id=5826 http://antwrp.gsfc.nasa.gov/apod/ap001127.html

Light pollution isn't a term the majority of the population in the United Kingdom may be familiar with or think about in day to day life in the 21st century, though it is something we should be thinking about in these modern times, especially with the current worries of global warming possibly accelerated by man's activities and the erasure of the night sky which man has used for thousands of years as a tool for navigation, science, art and a variety of religious beliefs. Millions of tons of carbon dioxide are being pumped out of power stations in the United Kingdom every year, as a result of feeding our habit for all things electric, outdoor lighting being a part in this process as we try and turn night into day in the name of safety and security. Energy is much on the agenda of politics in this age with the need to find renewable sources as the finite amount of naturally occurring energy sources will 'run dry' some time in the future and the use and viability of nuclear power is still hotly debated in the UK. We can all do something to help save energy now by cutting down on our use of electricity and energy, which would be the easy option just now, and not leave it all up to the government and local authorities.

In the past 30 - 40 years, we have increased our use of outdoor lights and streetlights by an extraordinary amount, more so in the past two decades with the rise in popularity of the outdoor (in-)'security' light, produced in bulk, usually sold as a 500W unit and sold very cheaply at that. Increases in the use of outdoor lighting for outdoor advertising, sports facilities, factories and so on contribute greatly to this modern scourge. What has happened as a result of our 'need' for outdoor lighting, is the erasure of the night sky, which used to be visible from many towns and cities in the past, when poets and writers jotted down their thoughts and artistic works, influenced by the majesty of the starry sky and the glow from the milky way above them. Many children nowadays are growing up not knowing what a proper starry night sky looks like because the veil of artificial light has blotted out everything bar the brightest stars and planets (many constellations of the zodiac previously visible cannot be seen nowadays in most places). It's also saddening to think that light which has travelled for many millions of years from distant stars and galaxies ends its journey to us blocked high above the ground from us as a result of light pollution!. Towns and cities enclosed in light domes aren't the only ones to suffer this affliction, the countryside is growing in popularity as people move from busy cities away from the rat race and other types of city pollution, and as a result, villages and small towns increase in size and the veil over them grows ever larger.

Another problem because of light pollution is the damage we are doing to the wildlife around us, who's activities count on the night being dark. Many forms of wildlife suffer from light pollution, from nocturnal animals like bats And hunting owls looking for their prey to lesser known creatures like glow worms who strive for the darkness for mating reasons they have been used to for millennia. Birds suffer from the lighting of their dark night time environment also, woken by our night time lights, chirping through the night thinking dawn is approaching. The link that follows is from an article from the Royal Society for the Protection of Birds (RSPB) on the nocturnal singing of daytime birds.

http://www.rspb.org.uk/birds/advice/nocturnalsong/index.asp

Types of Light Pollution

Light pollution can be broken down into three basic categories which are described below.

Light Spill / Light Trespass

Light spill and light trespass is the unwanted illumination of ones garden or property from neighbouring sites, be it residential, industrial, street lighting, etc. Light spill/trespass ranges from neighbouring garden's lights shining in your windows at night which may disrupt your ability to sleep properly, to poorly aimed lamps from properties by roadside's dangerously spilling light onto the road and oncoming drivers (example shown below), to astronomers wanting to enjoy the night sky from their property, though is severely hampered by stray light from neighbouring premises.

http://www.ile.org.uk/documents/RLP%202005.pdf

Light spill from a security light

Glare

Glare is the effect of directly seeing a lamp which is unshielded, too powerful or aimed irresponsibly. Glare from lamps is particularly dangerous when it occurs along roads and motorways as when driving and suddenly hit with the glare from a light your sight is temporarily affected as it tries to adjust to the sudden change in brightness and thus can result in accidents as you can't see as well as you did previously. For security reasons, glare from poorly directed lamps conceals rather than revealing the surroundings it is intended to, any would be intruder is hidden in the glare of the offending lamp instead of being seen if properly directed. It's also not a very welcoming sight for someone visiting your property!

glare from a security light No glare from a well directed security light

Skyglow

Skyglow is the term used to describe the glow that emanates outwards and upwards from cities, towns and villages from all types of lights combined, e.g., street lights, security lights, advertising, sports facilities, etc. Skyglow isn't hard to miss and is visible from all areas of the UK to some extent, worse around highly populated areas. Views of the night sky are very badly diminished and in some cities to the extent that only a handful of stars are visible on a clear night. The glow from large cities can still be seen from a dark site hundreds of kilometres away. Next time you are out in the countryside, take note of the amount of stars you see there compared to the town or city where you live.

Skyglow : wasted light and energy : looking towards the central belt of Scotland (note the reflection of the orange sky on the damp road surface miles away from any directly shone lamps)

What you can do

The solution to light pollution can be a very simple one, aim and use your outdoor lights responsibly and only when needed. People concerned about light pollution don't want lights turned off everywhere, lights are needed. What we want is outdoor lighting to be used and aimed responsibly to limit nuisance and energy waste and to reclaim the night sky for future generations, a starry sky which tens of millions of people cannot see nowadays.

The majority of residential gardens aren't very big and to illuminate one sufficient enough to see at night you only need a low wattage of bulb aimed in the right direction, i.e. down and not sideways. Up to 150W is more than enough to illuminate large gardens at night when needed. If you need to illuminate a large garden, use two lamps, in suited locations instead of one trying to light up all your garden from a distance.

The bulb I have in my outdoor lighting fixture is a 60W common household bulb (image below), the fixture is fitted with a PIR sensor so it's only on when I need it, this provides plenty of light to see what anyone is doing. The design of the fixture is also a full cut-off design with flat glass so no light shines above the horizontal when it's turned on.

A passive infra-red (PIR) motion sensor should be used as this not only means the light only comes on when needed cutting your electricity bill and saving energy, but also acts as a deterrent to any would be intruders when it comes on and startles them if they have entered your garden. If your garden is illuminated all night, any would be intruder can see clearly the layout of your garden and any potential obstacles!

If you need an all night light, make sure it points down and doesn't shine light into the sky or neighbouring premises, it should only illuminate the area needed. Consider using a low wattage compact fluorescent bulb in an all night light, which will cut down on your electricity use, there's a myriad of colours and wattages out there to buy which will suit your needs. Most halogen (in-)security lights on sale are overly bright for the intended purpose, i.e. 500W to lighten a garden or driveway, there are many alternatives which are more appealing for a residential property. Street lights in general, use lamps ranging from about 70W-300W, now there's food for thought! Other bad lamps designs include globe-lights and unshielded bulkheads, these types of lighting fixture throw light in all directions, especially globe-lights, which generally don't illuminate the area under them which is usually intended to be lit, which is no use if you want to light up the ground to see.

The bottom line is, if it's not needed, don't use it. Everyone and the environment will benefit.....