Blog | Light Pollution – What Is It and How Can We Reduce It?
The media often focusses its attention on air pollution, water pollution and soil pollution, but light pollution also has the potential to damage our health and negatively affect the environment around us.
So, what is light pollution exactly?
Light pollution is essentially the excessive use and unnecessary deployment of artificial lights to the natural night-time environment.
Environmental scientists generally divide light pollution into three principal categories:
• Skyglow is a description of the phenomenon when light that is emitted upward by upward directed or incompletely shielded lights or is reflected from the ground and scattered in the atmosphere, producing a luminous background. The effect can often be seen as a glowing dome of light over cities and towns, preventing inhabitants from enjoying a star lit sky. The main culprit is street lighting, which contributes fifty percent to the sky glow in urban areas.
• Over-illumination covers a number of issues including the following:
o A failure to use timers, occupancy sensors and other controls to extinguish lights when they are not required.
o Poor design, by specifying a higher level of illumination than is necessary for a given situation.
o Poor selection of fixtures or light bulbs, therefore not providing direct light into areas as needed.
o Poor selection of lighting system, requiring hardware to utilise more energy than necessary to accomplish the lighting task.
o Training of building managers and occupants not sufficient to ensure the efficient use of lighting systems.
o Poor lighting maintenance resulting in an increase in stray light and energy costs.
o “Daylight lighting” used by retailers to attract customers.
• Light trespass which occurs, for example, when unwanted light shines into a property from a neighbouring property causing issues such as sleep deprivation.
The Impact of Light Pollution
Light pollution disrupts the rhythm of diurnal species such as human beings that function to a biological clock of day and night. The consequences of this disruption can be sleep disorders, heightened anxiety, headaches and fatigue.
Wildlife can experience disorientation of time when there is too much artificial light at night.
Mammals, including bats and deer can experience difficulties foraging for food at night as a result of light pollution. Some of these mammals are at risk of exposure to predators and suffer increased mortality as a result of damage to their night vision. There is also evidence that there is a decline in reproduction leading to a shrinking population.
Birds such as owls and nighthawks hunt by moonlight and migrate at night. An abundance of artificial light can overwhelm the natural light source, resulting in birds being drawn to the artificial lights. The result of this is that birds deviate from their intended migration route, causing them to become exhausted, collapse, and fall prey to other animals. Marine birds are known to collide with lighthouses and other offshore sources of bright lights such as wind turbines and oil rigs.
For amphibians such as frogs and toads, the orange haze caused by light pollution confuses and disorients them, causing a decrease in both feeding and mating. The artificial light also impairs their natural instincts that protect them against natural predators and the elements.
Insects such as moths are well known to be naturally attracted to light and can use all their energy to stay near a source of light. This interferes with their mating and migration in addition to making them vulnerable to natural predators, which reduces their population. This has a knock-on effect on species that rely on insects for food or pollination.
Another concerning impact of light pollution suggested by experts is that nocturnal animals are avoiding artificially lit areas altogether, radically changing their normal behaviour. Some are wasting valuable energy taking longer routes to feeding grounds while others delay or even abandon feeding and mating routines. Conservationists are especially concerned about the British bat population, where numbers have declined so dramatically over the last century that all of the seventeen resident species are now protected by law.
Light pollution around lakes can prevent species of zooplankton from consuming surface algae causing algal blooms which negatively affects plant life and water quality in these lakes.
Aside from the negative impact on mammals, birds, amphibians and insects, light pollution is also associated with a huge waste of energy with estimates that in the US more than thirty million oil barrels and nine million tons of coal are wasted annually because of it.
Light pollution also impacts on atmospheric pollution as nitrate radicals which help control smog are destroyed in excessive artificial lights, increasing pollution in the atmosphere.
Reducing Light Pollution
Having identified the many negative aspects of light pollution, the question is whether or not we can do anything about it. The answer is yes, and here are several ways in which light pollution can be dramatically reduced.
• Switching to LED lights which are both an eco-friendlier and a brighter light option and can decrease the number of overall lights necessary.
• Shielding streetlights by fitting lamp fixtures which redirect the brightness of the bulb downward, avoiding the light shining into the night sky.
• Being more vigilant about switching off unneeded lights and if you are worried about safety, and choosing wavelengths which do not affect wildlife or insects. Additionally, the outdoor lights should be switched off when you are going to bed or you don’t have any work to do outside your house.
• Using automatic timers to put out streetlights and other outdoor lighting at a pre-scheduled time, avoiding them staying on when nobody is around, or it is light.
• Using motion and occupancy sensors in areas of sporadic use so that lights switch off automatically when not needed.
• Festival seasons consume a lot of lighting with many people keeping the bright lighting on throughout the day and night. Instead, using candles could be an effective alternative to lessen the impact, especially during the festive seasons.
• Using glare-free lights whenever possible and avoiding using vehicles that have a lighting system with a powerful glare. There are also many outdoor lighting alternatives which offer sky-friendly solutions and therefore homeowners should opt for certified low-glare fixtures, guaranteeing low-pollution lighting.
• Preventing outdoor lights such as garden lights from entering residential properties through windows and using lighting systems that do not glare at your neighbour’s window.
Learn More with Solareye
Here at solareye we are constantly looking for ways to reduce light pollution and its damaging impact, particularly on the bat population. We have developed the ‘Bat Hat’ which reduces the upwards light spillage of our omni directional LED by around 98%, meaning that it will neither bother the bats nor the insects as they fly overhead.