Since the advent of the Industrial Revolution, western societies have gotten into the habit of living in a world surrounded by light, both inside and outside the home, which allows people to pursue their activities after the sun has gone down. And yet, have you ever given any thought to the negative effects of an overly lit environment? The overriding consequence is light pollution of our cities! What can we do to counter this phenomenon?
WHAT IS LIGHT POLLUTION?
Light pollution is an occurrence that manifests itself at dusk. It is caused by an overabundance of misdirected, ineffective, and useless lighting systems, most notably in urban areas where artificial light sources such as street lamps, are used excessively.
The following shows how street lamps light our exterior spaces:
street lighting infography explaining the type of light emitted and how it can cause light pollution
Light projected by a street lamp can be deconstructed into three parts. Firstly, we have light that shines upwards, as represented by Zone A in the above diagram. This lighting angle is lost and useless to people walking around outside. It is also the predominant reason for the reduction of visibility of the stars in our city skylines. The Amateur Astronomers Federation of Québec has revealed that “97% of the populations of North America and Europe live in lighting-polluted skies”. Secondly, we have light that shines at a 10-degree angle above the horizon and that results in a glare, as identified by Zone B in the above diagram. This light is also detrimental to surrounding areas as it generates intrusive lighting. Finally, the last is the only true light, as defined by Zone C in the above diagram.
In light of the above, we need to ask ourselves a pertinent question: What future do we wish to offer generations to come?
HOW DOES LIGHT POLLUTION SHAPE OUR DAY-TO-DAY LIVES?
Artificial lights have replaced stars and darkness, which are harmful to human health. Scientists have noted that the production of melatonin is delayed when our circadian rhythm is exposed to excessive lighting. The circadian rhythm is the process that regulates our sleeping patterns. Consequently, with a disproportionate amount of light outside, the time it takes for our bodies to fall asleep at night is extended and our sleep is less than satisfactory. Over time, studies suggest that this might increase our risk of suffering from obesity, depression, diabetes, etc. We invite you to read our articles entitled ”LED and Its Possible Health Effects – Part 1 and Part 2” to learn more about the potential harm of artificial light on the general population.
We also need to consider how light pollution affects animals and their behaviour. We know that some species hunt, reproduce, migrate and hibernate in the dark. Intense brightness, at night, tends to disrupt the usual behaviour of these nocturnal animals; they confuse artificial light with the light of the moon. This disturbance can also affect the chances of survival of some prey who have adapted to darkness to better avoid nighttime predators. Thus, on a larger scale, excessive and useless lighting can have damaging repercussions on several ecosystems.
