Sources of Light Pollution

Whenever we look up into a clear night sky and see an orange glow rather than a myriad of sparkling magical stars, it is due to light pollution.

What Is Light Pollution?

Light pollution is any type of artificial lighting which produces a ‘nuisance level’ of ambient light and which prevents us from experiencing enough darkness so as to affect our health or our enjoyment.

What are the Sources of Light Pollution?

Examples of light pollution might be something like a street light which shines continuously through the night right outside your bedroom window or perhaps over-sensitive floodlights on a neighbour’s house which turn on and off during the night so as to affect your sleep. Other examples include general brightness or ‘sky glow’ when total darkness is preferred.

Star Gazing And Sky Glow

One of the most common complaints of light pollution is from astronomers. Due to the increasing amount ambient light from towns and cities, it is now very difficult to find a spot dark enough from which to see the stars properly.

Much of the lighting in cities is directed upwards and dispersed by moisture in the air, thus causing an orange-yellow ‘sky glow’. 90% of the country now has a glow at night and which prevents us from being able to see many stars.

Fast Pace Of Change

The change in our lighting over the past few decades has been enormous. Whereas fifty years ago, it would be a relatively common thing to experience the darkness, most people would now need to take a trip deep into the countryside to do so.

Street lighting, floodlighting, security lighting, the illumination of buildings, and an increase in the size of our towns and cities has all had a dramatic affect on the amount of ambient light that is in the atmosphere.

Light Pollution And Health

There is some evidence to suggest that a lack of darkness at night can also affect our health.

Researchers have found that there is a probability that too much light at night can disrupt our body clock and upset our bio-rhythms.

Melatonin, a hormone produced by the brain at night is thought to play an essential role in keeping our body clock functioning as it should, as well as in the regulation of oestrogen. It has been proposed that if this function is reduced or disrupted, then it could be a contributing factor in the development of some breast cancers.

There has also been speculation as to whether children who sleep in a room which is too light (if for example, they have a night-light left on), might be at risk of developing less good eyesight than those who sleep in total darkness.

In addition, a connection has been made between children who sleep in lighted rooms and higher levels of hyperactivity and stress.

Light Pollution And Wildlife

There is also evidence that too much light at the wrong times (i.e. at night, when darkness is meant to prevail) is also upsetting our wildlife.

There is concern that city birds get confused and wake at the wrong times, that the reduction in our moth population is partially due to them being attracted to lights which then kill them, and trees in well-lit towns and cities budding and dropping their leaves at the wrong times.

Nocturnal animals are disturbed by the lights and others are inappropriately attracted by it so that migrating birds for instance, are being harmed by colliding with lighted buildings.

Responsible Lighting

But it’s not all bad news. Campaigners against light pollution are not against artificial light at night per se. Rather; they would like to see more responsible lighting introduced which would not only keep light where its supposed to be, but also save wasted energy as well.

This means directing lights so that they shine downwards, towards the ground, where the light is needed rather than upwards into the sky. Also, light fittings could be designed in such a way to ensure there is no seepage or ‘light spill’ from the fittings. Lights illuminating buildings could be switched off during core night-time hours and unnecessary security lighting diminished.