Light Pollution: Research and Analysis

Electricity and electric light are one of the greatest inventions of man. This invention has changed our planet in a way that has never happened before in its 400 million years of history.

Light Pollution: Research and Analysis

Light Pollution: Research and Analysis


Electricity and electric light are one of the greatest inventions of man. This invention has changed our planet in a way that has never happened before in its 400 million years of history. Man has conquered the fear of darkness by discovering fire, but the invention of electric lights has removed the darkness from most of the darker parts of the planet. ‘Welcome to an illuminated world!’ But, did we ever think this light has its dark side too? It means darkness under the light. Intriguingly, the excessive use of lights is proven to be harmful to all the inhabitants of the earth. For instance, we can take this story seriously. 


On a cloud-free night in 1994, an earthquake struck the city of Los Angeles just before the dawn. There was no serious damage except for cut-off electricity in that area. The citizens, awakened from raw sleep, started to call in emergency departments. They are terrified to see a mysterious bright cloud over their heads! Later on, that mysterious bright cloud is actually the galaxy. The galaxy means our solar system and the location of our earth. Artificial citizens cannot see the stars in the dark sky because they covered their sky above by artificial lights. They never had a chance to look at the open sky in darkness. So, when they got the chance, they got horrified to see the natural sight. 


Darkness is always important in our life. From the dark evenings of the night that drag the earth to black sheets, it has an important role in the life of the earth's animals. We denied this essential fact and tried our best to shackle darkness with artificial lights. Now we work after dusk till dawn. There is nothing left to say about the life of darkness as it has become nonexistent in the developed areas. As a reaction to our unruly act, we are now realizing the importance of darkness. The massive use of lights introduces a new phenomenon that we know as “Light Pollution”. 




Light pollution which we also known as photo pollution, is the excessive presence of artificial and anthropogenic light in the night environment. If the natural conditions get disruption even if we use lights carefully, then imagine how immense the effects of excessive, misdirected or obtrusive uses of light can be. The rapid urbanization process accelerates light spreads, engulfing the darker areas. The light was a praiseworthy invention until its wastage, ‘light pollution’ came into being. Light pollution is of four types such as- light trespass, glare, sky glow, and light clutter. Even a single source of light can result in multiple forms of light pollution. A short description of them are as follows- 


  • Light trespass
  • The signboard “No Trespass” directs to stay out of here. But light is blind in to follow the instruction and goes beyond to the area where it is not supposed to. This is called light trespass, interrupting anyone's sleep. Spill light unintentionally illuminates other homes, businesses, or areas. It is the most common light pollution because there are no such guidelines to define or determine the time, place and quantity of light that can be proved unwanted. The street lights are the best example of spill light disturbing many citizens sleep.


  • Glare
  • Glare is a kind of visual impairment that occurs when the light is brighter than our eyes' capacity to tolerate it. Reduced contrast, color perception, and visual performance depend on glare’s intensity. Glares are also subdivided into three types; discomfort glare, disability glare, and blinding glare. 


  • Skyglow
  • A dome-like orange glow that covers the night sky is known as ‘Skyglow’. From natural lights to poorly designed and targeted man-made artificial lights are the main cause of skyglow. When the light reflected on the atmospheric dust and molecules, it creates skyglow. The skyglow affects us by the polarization of moonlight stopping nocturnal animal navigation, reducing the contrast between the stars and the galaxies and making it difficult to see celestial objects even with a telescope.


  • Light clutter
  • When an excessive grouping of bright lights creates confusion and distraction, we call it light clutter. This light pollution alone can contain the other three in itself. The most common example of light clutter is the unshielded street lights, competing with traffic and navigation signals.  


  • These four types of light pollution are the ultimate result of our accumulation of extra light to the environment. The extra light endangers the earth's ecosystem. Darkness dependent wildlife is at stake because the pollution affects their life cycle. Besides, we have a biochemical harmony in our body. The harmony of the light and the darkness makes it rhythmic and tidal. We changed this natural order by combining day and night together. Our forefathers looked at the night sky to understand the mystery of the motion of the earth and the seasons. They developed astronomical theories based on their observation without using a telescope. Later on, modern astronomy received success by researching the theories of their ancestors. The ancestors also understood when to harvest and reap. Today, we have no connection to the dark night sky. 




Light pollution was a light (not heavy) problem until it started affecting humans, wildlife, ecosystem, astronomy and the overall environment. The effects of light pollution are on-


  • Human health
  • For millions of years, the rhythmic commotion of day and night has also controlled our minds with our bodies. Circadian rhythm is the 24 hours cycle that regulates the physical, mental and behavioral changes in our body. Some physiologic activities like brain wave patterns, hormone production, and cell regulation are regulated by this rhythm. It is the reason why we sleep at night and work all day. But a recent survey of the last hundred years proves that the harmony is gone. Excessive light pollution can result in occurring many diseases like increased headache incidence, worker fatigue, medically defined stress, decrease in sexual function and an increase in anxiety. The people working at night shift are the worst sufferer of light pollution. These trends are more pronounced among employees working night shifts. In 2012, the World Health Organization has declared night work to be risky for cancer.




The pollution has an adverse effect on cancer too. For instance, a survey in 2007 in South Korea relates light pollution to breast cancer. Seoul is the highest in light pollution while Gangwon-do is the lowest. In comparison to breast cancer patients of the later one, Seoul has 34.4 percent more. 

Melatonin is an important hormone in our body controlling our sleep-wake cycle. Photon particles of light affect the gland in our brain that produces melatonin and thus affecting our natural bodily rhythms. Any impediment in melatonin flow can cause weight gain. It is thought that as a result of this, heart disease, diabetes, cancer, depression is increasing.   


  • Wildlife
  • All the important processes of wildlife such as feeding, sleeping, mating, and migration cycles are being threatened by luminous pollution. Too much artificial light at night can force wildlife to experience the disorientation of time. Mammals such as bats, raccoons, coyotes, deer, and moose can experience difficulty foraging for food at night. The night vision impairment causes an increase in the mortality rate. Nocturnal birds hunt and migrate at night. As they follow the natural light source while migrating, artificial lights distract them. Marine birds’ death rate has increased because of their attraction to the lights of high lighthouses, wind turbines, and drilling platforms at sea.


  • Sky glow’s orange haze affects amphibians such as frogs, toads, and salamanders in marshes and wetlands by confusing and disorienting them. It results in a decrease in their mating and feeding. They also lose their natural instincts to stay safe from predators and other elements. Bright coastal lights prevent many reptiles including sea turtles to hatch their eggs on the seashore as they prefer darker places. Artificial lights also disorient other nocturnal reptiles. Many insects like month are attracted to lights. The increase of artificial lights forces a number of insects to come near the light source and the predators of them may not reach them. Thus, it affects the whole ecosystem and creates ‘Ecological Light Pollution’. 


  • Astronomy
  • The ancient people made contributions to astronomy with empty eyes. Whereas, today's modern astronomical equipment like a telescope does not work properly because of light pollution. Light pollution like light spill and sky glow alters our view of the sky and stars by interfering with astronomical equipment. It makes faint celestial bodies nearly invisible and for this reason, light pollution has harmed astronomy the most.   
  • Observations on the Suomi NPP satellite say that one-third of the world's population now no longer see galaxies. Some over illuminated places like Singapore, Kuwait, and San Marino, cannot see 5.7 percent of the visible stars that can be seen from low illuminated places. The light pollution rate increased by 2 percent from 2012 to 2016. Most of the lights we use illuminate irreversibly. LED bulbs are energy savers, but they spread a blue light waves affecting the environment. 




So far, light pollution's effects are fearsome. We should come forward together to remove the darkness created by the light. Some of the preventive steps that we can take are-  


  • Use white light
  • Compact fluorescent lamps (CFL) and LED bulbs produce warm white lighting. White lighting does not scatter like blue short-wavelength light. Avoid using LED lights that emit a blue as it impairs night vision and adds to light pollution.


  • Cover light
  • Many covered lights are available in the market. These lights have covers on the upside stopping the light from going directly to the sky and thus prevent sky light pollution. 


  • Use cut off angles
  • Lights with cutoff angles keep the light where it is needed. Full cutoff, semi cutoff, cutoff, and non-cutoff are types of the cutoff. It minimizes up lighting, reduces high-angle brightness and improves visibility. 



  Information On Different Exterior Light Fixtures And Their Cutoff







  • Sensor it
  • The use of motion sensors can automatically turn outdoor fixtures and turn them off when needed. 


  • Get Certified
  • International Dark-Sky Association (IDA) is a nonprofit organization founded in 1988 with a group of expert and amateur astronomers. They aim at alleviating light pollution. They certify lights by maintaining Dark Sky Lighting. It means lights will not illuminate the sky and are designed to minimize glare, light spill, and sky glow. They provide and develop lights that do not disturb the environment.   


  • Turn off lights
  • We should turn the lights off when it is not necessary. It reduces light pollution and energy consumption


  • Create awareness
  • Raise awareness on individual, local and global levels can prevent light pollution. Close the blinds and curtains to prevent light spill. Office management can turn off or dim office lights after all workers have left the place every day. Business owners should dim lights on a fixed time to prevent light clutter and glare. The government can enact to reduce light pollution.