When you look up at the night sky, what do you see? If you're reading this post from a city, chances are you don't see very much. Whereas more than half of the UK enjoyed truly dark sky in the 1950s, only 10% do today. And it's a similar situation across the urbanised world. The culprit? Light pollution from poorly designed and excessive lighting.
Though lighting cities has economic and social benefits, poorly designed lighting comes at a cost. In addition to tainting our view of the milky way, light pollution has a negative impact on wildlife, affecting the migration of birds and the breeding patterns of nocturnal animals and insects. There are more downsides for us humans too – inefficient lighting costs the UK £1bn a year as welldisrupting our sleeping patterns (I'm not sure which is worse!)
So what can be done?Truthfully, reducing light pollution is a pretty straightforward task:
1. Install motion sensitive lighting
If a tree falls in the forest and there's no one around to hear it, does it… ok, let's not go there. But when there's no one in the street, do we need street lighting? Motion sensitive street lighting is a pretty selfexplanatoryidea, and one that has become reality on this Barcelona street. Lights come on as people and moving objects approach, illuminating an area in advance, therefore reducing the amount of wasted light emitted from the street. Deployed across an entire city, the results could be impressive.
2. Ensure bulbs are covered and lighting faces downwards
Good street lighting should feature a bulb which is encased above and to the sides. This channels light downwards -where it is needed – and reduces the amount of wasted light. Known as 'cutting off light at the horizontal', this ensures that light is used to illuminate the ground, not the sky.
3. Use a different kind of light
Switching to low watt bulbs is a straightforward way of reducing light pollution, albeit one that could not be deployed across every piece of outdoor lighting in a city. Moving away from bluish-white lighting could be a bigger contributor to reduced light pollution on an urban scale. LED outdoor lighting, whilst energy-efficient, often emits a blue light which creates more light pollution. This can be avoided with warm-white lighting. The Spanish market city ofVélez-Málaga (seems the Spanish are big on lighting innovation) recently adopted a dimmable warm-white light system for its streets, giving it lower watt lighting on demand and better illuminating its historic streets in the process.
4. Minimise light loss from your home
Reducing light pollution is not just a task for your municipal government. Outdoor lighting on buildings and in gardens contributes to light pollution, as does lightingemittedfrom inside buildings. Obviously, some lighting is more critical than others (see above), but by following the above three steps on outdoor lighting, and doing a better job of minimising the amount of light lost from the inside of your home, everyone can play a part in reducing urban light pollution.
Image courtesy of Cestomano on flickr
FAQs
Dimmers, motion sensors, and timers can help to reduce average illumination levels and save even more energy. Outdoor lighting fixtures that shield the light source to minimize glare and light trespass help prevent light pollution.
How to reduce light pollution in cities? ›
Dimmers, motion sensors, and timers can help to reduce average illumination levels and save even more energy. Outdoor lighting fixtures that shield the light source to minimize glare and light trespass help prevent light pollution.
What are 4 types of effects of light pollution? ›
Glare — excessive brightness that causes visual discomfort. Sky glow — brightening of the night sky over inhabited areas. Light trespass — light falling where it is not intended or needed. Clutter — bright, confusing, and excessive groupings of light sources.
What are 2 solutions of light pollution? ›
Second, take control of your own lights at home by installing shielded fixtures, turning unnecessary lights off at night, or using motion sensors. Third, become active in your community by helping to create or enforce a lighting ordinance that creates the kind and level of lighting you want in your community.
What are 10 ways to reduce light pollution? ›
Methods to minimize the light pollution are : Consider replacing outdoor lights with intelligently designed, low-glare fixtures. Place motion sensors on essential outdoor lamps. Replace conventional high-energy bulbs with efficient outdoor C F L s and L E D floodlights.
What are 10 ways to reduce pollution? ›
What you can do about air pollution
- Drive your car less. ...
- Keep your car in good repair. ...
- Turn off your engine. ...
- Don't burn your garbage. ...
- Limit backyards fire in the city. ...
- Plant and care for trees. ...
- Switch to electric or hand-powered lawn equipment. ...
- Use less energy.
Research suggests that artificial light at night can negatively affect human health, increasing risks for obesity, depression, sleep disorders, diabetes, breast cancer and more. What is light pollution? “Many species (including humans) need darkness to survive and thrive.”
What are 4 things that cause pollution? ›
Vehicle emissions, fuel oils and natural gas to heat homes, by-products of manufacturing and power generation, particularly coal-fueled power plants, and fumes from chemical production are the primary sources of human-made air pollution.
What are 4 ways air pollution affects the environment? ›
Air pollution affects all things. It is harmful to our health, and it impacts the environment by reducing visibility and blocking sunlight, causing acid rain, and harming forests, wildlife, and agriculture.
How to reduce pollution? ›
What you can do
- Commute smart by walking or riding to work or the shops instead of driving. ...
- Choose a fuel-efficient vehicle next time you are replacing your car. ...
- Save energy, by turning off the television and make sure you flick the light switch when you leave the room. ...
- Buy energy -efficient appliances.
Light pollution severely disrupts nocturnal ecosystems, interferes with the natural rhythms of plants and animals, mars the wilderness experience and landscape beauty, carries risks to human health and safety, and wastes energy.
What are 5 facts about light pollution? ›
Did you know that:
- At least 30% of outdoor lighting is wasted, releasing atmospheric pollutants. ...
- In the UK, wasted lighting energy costs millions. ...
- Poorly designed and installed lighting causes glare and skyglow. ...
- UK planning regulations cannot deal with poor lighting. ...
- Brighter lighting does not mean improved security.
According to an article in Sky & Telescope magazine [2], disruption of the circadian rhythm has been linked to sleep disorders like insomnia and delayed sleep-phase syndrome, as well as depression, hypertension, attention deficit disorder, obesity, diabetes, and heart disease.
How can light pollution be improved? ›
The best way to prevent light pollution is to avoid the use of any outdoor lights. 2. Use white light low-energy LED lamps. Avoid orange or pink sodium lights which have an urbanising effect and are less energy efficient.
What are some examples of reducing light pollution? ›
Unlike removing pollution from the air or water, light pollution can be eliminated immediately. Reducing light pollution can be as simple as turning off the lights, installing motion sensors that limit when lights are on, or adding dimmers that reduce the light coming from a single bulb.
