Brian Barton
Light pollution is the presence of unwanted, inappropriate, or excessive artificial lighting. It is caused by the human-made alteration of outdoor light levels from those occurring naturally. This can be due to a variety of factors, including poorly designed lighting, such as unshielded light fixtures, that allow light to shine outward and upward into the sky instead of focusing it downward. Sources of light pollution include streetlights, parking lots, exterior lights on homes and businesses, and illuminated signs. Light pollution has detrimental effects on human health, wildlife, and the environment, including sleep deprivation, confusion in migrating birds, and negative impacts on plant and animal physiology. It also reduces the visibility of the night sky, affecting astronomers' ability to observe celestial objects and disrupting the natural diurnal patterns of light and dark that orchestrate the rhythm of life. Addressing light pollution involves implementing better lighting practices, such as using shielded lights, reducing unnecessary lighting, and advocating for local legislation to control light pollution.
| Characteristics | Values |
|---|---|
| Definition | The human-made alteration of outdoor light levels from those occurring naturally |
| Sources | Streetlights, greenhouses, satellites, boats, buildings, street lights, fireworks, exterior lights, shopping malls, neon signs, illuminated signboards, unshielded light fixtures, landscape lights, party lights, sports lighting, automobiles, plastics, light from cars, offices, factories, outdoor advertising |
| Effects | Sleep deprivation, fatigue, headaches, stress, anxiety, other health problems, cancer, reduced melatonin levels, harm to wildlife, negative impact on plant and animal physiology, confusion in animal navigation, altered competitive interactions, changed predator-prey relations, ecological damage, algal blooms, reduced water quality, impact on insect development and reproduction, species decline of plants, sky glow, glare, light trespass, clutter |
| Impact | 83% of the world's population lives under light-polluted skies, 23% of the world's land area is affected by skyglow, 80% of Americans and 60% of Europeans cannot see the Milky Way, 3.36 trillion dollars per year in ecosystem damages, 20-50% of outdoor lighting contributes to light pollution, 1/3 of lighting is wasted at an annual cost of $2.2 billion |
| Solutions | Turn off unnecessary lights, use shielded light fixtures, use less powerful lamps or bulbs, use compact fluorescent lamps (CFL) and LED bulbs, use warm white lighting, use dark sky and turtle-safe outdoor lighting, use fully shielded and light-efficient fixtures, use well-designed light fixtures with a full cut-off design, improve outdoor lighting practices, use timers, sensors, or shut off lights when not in use, local legislation and advocacy |
What You'll Learn
- Light pollution is the human-made alteration of outdoor light levels from those occurring naturally
- Sources of light pollution include streetlights, buildings, boats, and even fireworks
- Light pollution has detrimental effects on human health, such as sleep deprivation, fatigue, and headaches
- Light pollution negatively impacts wildlife, such as birds, sea turtles, and insects
- Light pollution can be reduced by using shielded lights, turning off unnecessary lights, and improving lighting practices
Light pollution is the human-made alteration of outdoor light levels from those occurring naturally
The primary cause of light pollution is outdoor lights that emit light in the wrong direction. Any light that escapes upwards will scatter throughout the atmosphere, brightening the night sky and diminishing our view of it. This is known as "sky glow". Light fixtures that direct all light downward greatly reduce the amount of light pollution and are referred to as shielded or full cut-off lights.
Light pollution has detrimental effects on human health, wildlife, and the environment. It can cause sleep deprivation, fatigue, headaches, stress, anxiety, and other health problems in humans. It also disrupts the natural body rhythms and circadian rhythm of both humans and animals, as darkness is essential to our biological welfare.
Additionally, light pollution can confuse animal navigation, alter competitive interactions, change predator-prey relations, and cause physiological harm. For example, sea turtle hatchlings instinctively head towards the brightest source of light, which used to be starlight reflecting off the ocean. Now, with coastal cities flooding the night with bright lights, the hatchlings become disoriented and fall prey to dehydration and predation.
Light pollution also has economic impacts, with one-third of all lighting being wasted at an annual cost of $2.2 billion. It also affects astronomers' ability to view celestial objects and can reduce the perception of solitude and naturalness in natural landscapes.
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Sources of light pollution include streetlights, buildings, boats, and even fireworks
Light pollution is the presence of any unwanted, inappropriate, or excessive artificial lighting. It is a major side effect of urbanisation, and 83% of the world's population is estimated to live under light-polluted skies. Sources of light pollution include streetlights, buildings, boats, and even fireworks.
Streetlights are a major contributor to light pollution. Poorly designed streetlights allow light to escape upwards and sideways, brightening the night sky and diminishing our view of it. This is known as sky glow, and it is particularly prevalent over urban areas due to the electric lights of streetlamps, offices, and factories. Streetlights can also cause light trespass, where unwanted light enters adjacent properties, and glare, where excessive brightness causes visual discomfort.
Buildings are another source of light pollution, especially when they are illuminated by exterior lights or neon signs. Like streetlights, buildings can contribute to sky glow and light trespass when they are poorly lit. In addition, buildings with large windows can allow light to escape upwards and outwards, contributing to light pollution.
Boats can also contribute to light pollution, particularly in harbours and other coastal areas. Like buildings and streetlights, boats can cause light trespass and sky glow if they are poorly lit. In addition, the movement of boats on the water can create a dynamic light pollution source, impacting the surrounding environment.
Even fireworks, which are often enjoyed as a form of entertainment, can contribute to light pollution. Fireworks release bright lights into the sky, which can be disruptive to both people and animals in the area. The impact of fireworks on light pollution can be particularly noticeable during festivals and celebrations, where large numbers of fireworks are set off in a short period.
Overall, these sources of light pollution can have significant impacts on both human health and the environment. By understanding the sources of light pollution, we can take steps to reduce its effects, such as using shielded lights that direct light downward and turning off unnecessary lights.
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Light pollution has detrimental effects on human health, such as sleep deprivation, fatigue, and headaches
Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. It is caused by a variety of factors, including outdoor electrical lights, sports lighting, streetlights, and greenhouses, which send light upward into the sky instead of downward, where it is needed. This can have detrimental effects on human health, including sleep deprivation, fatigue, and headaches.
Sleep deprivation caused by light pollution can disrupt normal sleep patterns, decrease total sleep time, and increase REM sleep. This can lead to fatigue and decreased sleep efficiency. It can also aggravate dry eye symptoms and cause a rapid breakup of tear film, leading to ocular fatigue.
Poorly designed lighting at outdoor sports centers, fields, and stadiums can cause increased light pollution, affecting the sleep and health of nearby residents. Additionally, light pollution from streetlights and greenhouses can result in light trespass, where light falls into areas where it is not intended, wanted, or needed.
The growing awareness of the detrimental effects of light pollution has led to efforts to reduce it. These include advocating for responsible outdoor lighting practices, such as using timers, sensors, or simply turning off lights when not in use, as well as working with communities to establish codes and statutes that reduce light pollution. Properly designed lighting can help minimize its negative impacts on human health while still being beautiful, healthy, and functional.
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Light pollution negatively impacts wildlife, such as birds, sea turtles, and insects
Light pollution, the human-made alteration of outdoor light levels from those occurring naturally, negatively impacts wildlife, including birds, sea turtles, and insects.
Birds
Billions of birds rely on the natural cycles of day and night to navigate their nighttime migrations. Artificial light throws birds off their migration paths, entrapping them and causing them to circle lit areas, which can deplete their energy and put them at risk of colliding with buildings and infrastructure. This phenomenon is especially common on nights with low-hanging clouds or fog, when birds tend to fly at lower altitudes. To avoid these dangers, birds should be drawn away from lights and towards darkness. BirdCast, for example, helps people know when birds are migrating so that they can make changes to lighting when it matters most.
Sea Turtles
Beaches lined with condominiums, houses, hotels, and restaurants emit powerful, white lights that cause sea turtles to crawl towards them (misorientation) or crawl in circles on the beach (disorientation). Excess lighting draws hatchlings towards land, where they may be eaten by predators, run over, or drown in swimming pools. To reduce light pollution that affects sea turtles, coastal communities have passed ordinances requiring residents to turn off beachfront lights during turtle nesting season. However, these ordinances are not always enforced, and they do not address the larger problem of sky glow near cities.
Insects
About half of the millions of insect species on Earth are nocturnal, so artificial light can significantly impact their life cycles. Excess light makes it difficult for some species, like fireflies, to find mates. Some insects use polarized light to find bodies of water where they breed, and reflections from outdoor fixtures confuse their sense of direction. Insects are also attracted to the headlights of moving cars, with an estimated 100 billion insects meeting their end on German highways each summer. Artificial light also interferes with the way some insects hunt at night.
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Light pollution can be reduced by using shielded lights, turning off unnecessary lights, and improving lighting practices
Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. It has harmful effects on wildlife habitats, human health, and the climate. Light pollution can be reduced in several ways, including the use of shielded lights, turning off unnecessary lights, and improving lighting practices.
Using shielded lights is an effective way to minimise light trespass and glare, ensuring that light is directed only where it is needed. Light shields, also known as light shrouds or glare shields, are accessories that can be attached to the top and/or sides of light fixtures to focus the light downward or inward. This prevents light from spreading to unwanted areas and reduces its negative impact on the environment.
Turning off unnecessary lights is another simple yet impactful way to reduce light pollution. Decorative lighting, for example, is often left on even when no one is using or enjoying it. By being mindful and turning off lights when they are not in use, we can significantly reduce light pollution and its associated energy waste.
Improving lighting practices involves choosing better outdoor lighting options that minimise light pollution. LED lights, for example, have a more focused light beam and produce less spillover into unwanted areas. They also have a longer lifespan, use less energy, offer better light quality, and have superior dimming capabilities. Additionally, dimmers, motion sensors, and timers can be used to reduce average illumination levels and save energy.
By implementing these strategies, such as using shielded lights, turning off unnecessary lights, and adopting improved lighting practices, we can collectively make a significant difference in reducing light pollution and mitigating its harmful effects on the environment, wildlife, and our well-being.
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Frequently asked questions
Light pollution is the presence of any unwanted, inappropriate, or excessive artificial lighting. It is a major side effect of urbanization, with 83% of the world's population living under light-polluted skies.
Light pollution is largely caused by bad lighting design, which allows artificial light to shine outward and upward into the sky, instead of focusing it downward. Common sources of light pollution include street lamps, shopping mall lights, exterior lights found on most homes/businesses, and illuminated signboards.
Light pollution has detrimental impacts on human health, wildlife, and the environment. It can cause sleep deprivation, fatigue, headaches, stress, anxiety, and other health problems. It also confuses the internal, twenty-four-hour clock that guides day and night activities and affects physiological processes in nearly all living beings.
Light pollution can be reduced by utilizing a less powerful lamp or bulb, using shielded lights that direct light downward, and turning off unnecessary outdoor lights.
