Light Pollution In a Nut Shell
You remember the days when we were challenged to count the stars in the sky and how difficult it used to be but nowadays it is pretty much very easy. So, what exactly happened? from the title it’s pretty clear that it is because of light pollution. So, what is light pollution?
In simple terms, light pollution is nothing but the excessive presence of man-made artificial lights in the night environment. It brightens the night sky which makes it difficult for us to watch the stars. Light pollution is the side effect of urbanization. Too much light pollution has consequences it washes out starlight in the night sky, interferes with astronomical research, disrupts ecosystems, has adverse health effects, and wastes energy.
Of all the pollutions caused by humans, light pollution is the easiest one to fix just turning off the lights will do the trick but unfortunately, there is very little awareness about light pollution.
Obviously, we cannot totally avoid artificial lights the mankind depends on them for multiple reasons like street lights, car headlights, e.t.c
Some of the major sources of light pollution are skyscrapers, cars, street lights, and many more. These sources are categorized into different types.
It’s a kind of light pollution that occurs when unwanted light enters one’s property and affects living mostly. It causes sleep deprivation. Most light trespass pollution is caused by unused lighting by the neighbors which are left out all night long, roadway lighting, and unnecessary street lights.
As the name suggests Over-illumination is the excessive use of light. Unnecessary electric lighting is expensive and energy-intensive. It can be caused by multiple factors like unnecessary lights in an unoccupied area, using artificial lights instead of natural light, e.t.c
Glare is defined as the difficulty of seeing in the presence of bright light such as stadium lights, direct sunlight, car lamps, e.t.c. Glare light scattering in the eye causes loss of contrast, sometimes blinds you temporarily, and leads to unsafe driving conditions which may cause accidents, these types of accidents are very common.
It happens when too many artificial glow up the whole sky apart from the natural sources of light like the sun, moon, stars, and the light reflected from each other, etc. It can be easily observed when looking at a well-lit urban city.
Light clutter refers to excessive groupings of lights. All the badly designed street lights and over bright advertisements are examples of light clutter and it's obvious that such excessive grouping of lights may distract and cause accidents just like in the case of a glare. This kind of light pollution contributes to the above types like sky glow, trespass, glare, and over-illumination.
It’s the worst of all this kind of light pollution occurs when the light goes directly up into the sky and lost in space and serves no useful purpose. It's atmospheric scattering artificially brightens the night sky which makes it difficult to watch the night sky. It is just a wasted light and energy resource.
You can understand all the above in just one picture
So how is light pollution measured?
Measuring light pollution involves determining the illumination of a particular place and illumination is nothing but the number of light photons per unit area. This can be calculated using a common and more friendly device called SQM(Sky Quality Meter) in the unit of mag/sec2. The device is very small, easy to use, and almost very accurate. Below is the picture of how the device looks.
Bortle Scale is another way to measure light pollution. It has 9 levels on the scale to measure the night sky’s brightness. This is again based on the SQM.
Here is a great resource to view the SQM values across the world.
What are the effects of light pollution?
Light pollution has a wide variety of negative effects on humans, as well as wildlife, and protecting the night sky is a valuable step to conserving biodiversity. Most people think that, as we sleep at night, the rest of the species do the same which is not the case in fact most of the other species actually start their real day after the sun is down which helps them to hunt, migrate, find shelter, find mates to reproduce, etc such biological activities are highly affected by the artificial lighting at nights.
Light pollution affects the movement of animals at night in search of food or shelter. A lot of animals actually use natural light for navigation for example turtles use the light from the horizon of the ocean to navigate their way underwater but these artificial lights navigate them to the cities and a lot of them die on their way. Bats are very sensitive to light and cannot move to other places(Well I don't care much about them now).
Many birds migrate at night they use the natural light from the moon and stars to migrate but now they are wrongly navigated to the urban cities to those well-lit buildings which affect their migration cycle in turn affect their food and shelter. Few birds are actually trapped in the urban cities because of the lights and starve to death as the cities offer them less food.
Many species of plants bloom in the absence of light. They are mostly pollinated by insects, bats, or smaller animals. Increasing the lighting conditions around them may prohibit them from ever flowering and thus reproducing.
Let’s not neglect the fact of the amount co2 we produce to generate the electricity which is not efficiently used. It not only pollutes the environment but also costs a lot of money and useful resources.
Effects of light pollution on human health
Of course, most of us don't care abt the wildlife so at least think of the consequences of light pollution on our human health.
All life forms have relied on Earth’s predictable rhythm of day and night. It’s encoded in the DNA of all plants and animals. Humans have radically disrupted this cycle by lighting up the night. Excessive light exposure can have adverse effects on human health which includes headache, anxiety, increase in stress, depression, insomnia, cancer, cardiovascular disease, etc
Melatonin is a naturally occurring hormone that is released by darkness. It serves many functions in the human body and any deficiency of it can affect the sleep and wake cycle which will cause depression and insomnia,
Blue Light is a type of light produced by LED lights, computer screens, TV screens, and phone screens. This kind of light can penetrate all the way to the retina and can damage cells there which can lead to eye damage and even permanent blindness.
So let’s look at what we are missing
Lockdown has given a chance to a lot of people to see how the night sky actually looks like. I have seen a lot of pictures taken during the lockdown which were absolutely stunning.
Do you know that 33% percent of the world actually cannot see the night sky and in urban cities, almost 99% of them cannot see it.
So what can we do?
I am not saying light pollution is the most critical pollution of all but it is definitely the easiest one to solve in a very short period of time compared to others.
- Minimize the exterior lighting by using proper light fixtures.
- Minimize the unused light
- Use light only when necessary
- Choose lights that are dark sky approved
- Using motion sensor or timers are the best way to optimize the light exposure and also a great hack to save some money.
- Avoid blue lights
- Switch to LED’s
- Educate others on the night sky and its effects on human and wildlife
If you have any great night sky experiences or pictures which you would like to share do drop me a mail-in here or drop them in comments and if you have any suggestions do drop a comment.