Managing Light Pollution: Strategies For Humans

Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. It has harmful effects on human health, wildlife, and the environment. It can cause sleep disorders, depression, cardiovascular disease, cancer, and other health issues in humans. It also disrupts the natural behaviours of animals, such as migration patterns, wake-sleep habits, and habitat formation. To manage light pollution, humans can use fully shielded, light-efficient fixtures, and reduce the use of blue light, which has been linked to adverse health effects. Additionally, individuals can use outdoor lighting only when and where it is needed and ensure that outdoor lights are properly shielded, directing light down instead of up into the sky.

Use low-pressure sodium lights

Light pollution is a pressing issue that affects wildlife, ecosystems, energy consumption, and human health. It is caused by the human-made alteration of outdoor light levels, which can have harmful effects on both the environment and people.

One way to manage light pollution is to use low-pressure sodium lights. Low-pressure sodium lamps are highly efficient electrical light sources that produce light with a characteristic wavelength near 589 nm, resulting in a yellow hue. While this restricts their use to outdoor lighting applications where colour vision is not a requirement, such as street lamps, they offer several advantages in reducing light pollution.

Firstly, low-pressure sodium lights emit light on only two dominant spectral lines, with other much weaker lines present. This limited spectral output means they produce the least spectral interference with astronomical observation. This is particularly important for locations near astronomical observatories or areas that need protection from light pollution, such as sea turtle nesting beaches. By minimising spectral interference, low-pressure sodium lights help preserve the night sky for scientific research and protect wildlife that relies on natural light cues.

Secondly, the yellow colour of low-pressure sodium lamps leads to the least visual sky glow. This is due to the Purkinje shift of dark-adapted human vision, which causes the eye to be relatively insensitive to the yellow light scattered at low luminance levels in the clear atmosphere. As a result, low-pressure sodium lights minimise the amount of light pollution that escapes into the sky, reducing the collective light pollution found over big cities, known as sky glow.

Additionally, low-pressure sodium lamps are highly efficient in terms of energy consumption. They are among the most efficient electrical light sources when measured in photopic lighting conditions, producing above 100 and up to 206 lm/W. This high efficiency is partly due to the light emitted being at a wavelength near the peak sensitivity of the human eye, which means less light is required to achieve the same level of illumination. By reducing energy consumption, low-pressure sodium lamps help decrease the environmental impact of light pollution, lowering carbon dioxide emissions and mitigating climate change.

Furthermore, low-pressure sodium lamps have a long service life of about 18,000 hours, and they do not decline in lumen output over time. This is in contrast to mercury vapour high-intensity discharge lamps, which become dimmer towards the end of their life while continuing to consume the same amount of electrical power. The consistent light output of low-pressure sodium lamps ensures that areas remain adequately illuminated over time, maintaining safety and reducing the potential for light trespass, where unwanted light escapes into adjacent properties.

In summary, the use of low-pressure sodium lights is an effective strategy for managing light pollution. They minimise spectral interference, reduce sky glow due to their yellow colour, are energy-efficient, and provide consistent illumination over their long service life. By adopting these lights in appropriate outdoor lighting applications, communities can help mitigate the negative impacts of light pollution on the environment and human health while still maintaining the necessary illumination for safety and functionality.

Avoid blue lights

Blue light has a significant impact on human health and the environment. Research shows that exposure to blue light at night negatively affects the body's biological clock, known as the circadian rhythm. This disruption can lead to sleep disorders, depression, diabetes, heart disease, and obesity. Additionally, blue light suppresses the production of melatonin, a hormone that regulates sleep, immune responses, and metabolism.

To avoid the adverse effects of blue light, it is recommended to minimise exposure to blue light, especially after dusk. Here are some ways to avoid blue light and reduce its impact:

• Use "warm" toned lighting: Opt for warm-toned or filtered LEDs with a correlated colour temperature (CCT) of 3000 Kelvin or lower. These bulbs emit less blue light and can be dimmed to reduce illumination levels.
• Shield lighting fixtures: Use fully shielded light fixtures that emit no light upward. This prevents light trespass and reduces sky glow, a common issue in light pollution.
• Minimise screen time before bed: Avoid looking at bright screens, such as computers, TVs, and smartphones, beginning two to three hours before bedtime. These electronic devices emit blue light, which can disrupt your sleep.
• Wear blue-light-blocking glasses: If you work the night shift or use electronic devices frequently at night, consider investing in glasses that block out blue light. These glasses can help protect your eyes and improve your sleep.
• Utilise colour temperature apps: Install apps on your electronic devices that adapt the screen colours to the time of day. During the day, opt for "cool" appearing light, and at night, switch to "warm" appearing light.
• Dimmers, timers, and motion sensors: Use dimmers to lower light intensity and reduce glare. Timers and motion sensors can automatically turn off lights when not in use, conserving energy and minimising light pollution.
• Turn off unnecessary lights: Unoccupied buildings, especially offices, should have their lights turned off at night. This simple action can prevent indoor light from leaking into the night sky and contributing to light pollution.

By following these guidelines, we can reduce our exposure to blue light, improve our health and sleep, and contribute to the preservation of dark skies and the environment.

Turn off unnecessary lights

Turning off unnecessary lights is one of the most effective ways to reduce light pollution. Light pollution is caused by inefficient or excessive artificial light, and turning off unnecessary lights can help mitigate this issue.

Reducing Light Trespass and Sky Glow

Turning off unnecessary indoor lighting, especially in empty buildings at night, helps prevent light trespass, where artificial light spills into unwanted areas. This also helps reduce sky glow, an artificial glowing in the night sky caused by light pollution, which obscures the stars and brightens the sky.

Protecting Wildlife and Ecosystems

Light pollution can have detrimental effects on wildlife and ecosystems. It interferes with the life cycles and behaviours of many species, such as the hunting patterns of nocturnal predators and the mating habits of wetland amphibians. Migratory birds can be disoriented by artificial light, causing them to begin their migration too early. Additionally, light pollution can attract insects, leading to their deaths, and disrupt the behaviour of marine creatures like corals.

Improving Human Health and Wellbeing

Artificial light at night can negatively impact human health and wellbeing. It disrupts the natural circadian rhythm, which is essential for maintaining a healthy sleep-wake cycle. Exposure to bright light at night can halt the production of melatonin, a hormone that regulates sleep, immune responses, and metabolism. Reducing light pollution by turning off unnecessary lights can help mitigate these negative effects on human health.

Conserving Energy and Resources

Turning off unnecessary lights also has economic and environmental benefits. The International Dark-Sky Association estimates that one-third of all lighting is wasted, costing $2.2 billion annually in the US alone. Reducing light pollution by turning off unnecessary lights can lead to significant energy savings and reduce the environmental impact of electricity generation.

Taking Action

Individuals can play a crucial role in reducing light pollution by turning off unnecessary lights in their homes and workplaces. Closing blinds or curtains at night can also help minimise light trespass and sky glow. Spreading awareness about light pollution and its impacts can encourage others to take similar actions. Additionally, individuals can advocate for better lighting practices in their communities, such as using shielded, downward-facing lights and motion sensors to reduce light pollution further.

Shield outdoor lights

Shielding outdoor lights is an effective way to manage light pollution. Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. It has harmful effects on wildlife, ecosystems, human health, and energy and climate change.

Outdoor light shields are an easy and excellent way to block the rays of outdoor lights from trespassing. They are partial shields that stop the direction of light in one or more directions. Light shields can be used to block rays from travelling upwards to comply with dark sky rules, or sideways to help out a neighbour. Light shields are usually made of metal and can be glued or welded onto the light. They are simple to install, but it is important to be confident about what you want to achieve before installing them, as they are hard to fix once they are in place.

Light shields can be used to reduce glare, sky glow, and light trespass. Glare from poorly shielded outdoor lighting can harm human health by decreasing vision and reducing contrast, which limits our ability to see potential dangers at night. Aging eyes are especially affected. Light shields can also help to reduce sky glow, which is the collective light pollution found over big cities. This can obscure the night sky, making it difficult to see the stars.

In addition to their environmental benefits, light shields can also help to improve relationships with neighbours. Obtrusive lighting can cause problems for neighbours by disrupting their sleep or making it difficult for them to see properly at night. By installing a light shield, you can be a good neighbour by being considerate of others.

Overall, shielding outdoor lights is an effective way to manage light pollution, reduce its negative impacts on human health and the environment, and improve relationships with neighbours.

Use dimmers, motion sensors, and timers

Light pollution is a pressing issue that has harmful effects on human health, wildlife, and the environment. It is caused by the excessive or inappropriate use of outdoor artificial light, and it is something that everyone can help to reduce.

One way to reduce light pollution is to use dimmers, motion sensors, and timers. These tools can help to reduce average illumination levels and save energy. Here are some ways to implement them:

Dimmers

Dimming lights can help to provide the right amount of light while reducing glare and saving energy. By lowering the light intensity, you can still benefit from the functionality of lighting while minimising its negative impact. This is especially useful in outdoor settings where light fixtures often produce more light than is necessary.

Motion Sensors

Motion sensors are an effective way to ensure that lights are only activated when needed. This can be particularly useful in outdoor spaces or areas that are not frequently occupied. By using motion sensors, you can reduce the amount of time that lights are unnecessarily left on, thereby decreasing light pollution and conserving energy.

Timers

Timers are another useful tool to automate lighting and ensure that lights are turned off when they are not required. This is especially beneficial for indoor spaces, such as empty offices or buildings at night, to prevent light leakage into the night sky. Timers can also be used to adjust lighting levels according to the time of day, providing brighter lighting during the day and dimmer lighting at night.

By implementing these strategies, you can help to reduce light pollution, conserve energy, and minimise the negative impacts of artificial lighting on human health, wildlife, and the environment. These simple measures can contribute to a more sustainable and environmentally friendly approach to lighting.

Frequently asked questions