Light Pollution and Impact of Light Pollution

Subject :Environment

Section: Pollution

Light Pollution:

Light pollution can be defined as the introduction by humans, directly or indirectly, of artificial light into the environment.
Avoidable light pollution refers to light flow emitted at night by artificial light sources which are inappropriate in intensity, direction and/or spectral range, unnecessary to carry out the function they are intended for, or when artificial lighting is used in particular sites, such as observatories, natural areas or sensitive landscapes.

Types of Light pollution:

Light trespass: When unwanted light enters one’s property, for instance, by shining over a neighbour’s fence.
Over-illumination: It is the excessive use of light.
Glare: Glare is often the result of excessive contrast between bright and dark areas in the field of view.
1. Blind glare: describes effects such as that caused by staring into the Sun. It is completely blinding and leaves temporary or permanent vision deficiencies.
2. Disability glare: describes effects such as being blinded by an oncoming cars lights, or light scattering in fog or in the eye reduces contrast, as well as reflections from print and other dark areas that render them bright, with significant reduction in sight capabilities.
3. Discomfort glare: does not typically cause a dangerous situation in itself, and is annoying and irritating at best. It can potentially cause fatigue if experienced over extended periods.
Clutter: Clutter refers to excessive groupings of lights. Groupings of lights may generate confusion, distract from obstacles (including those that they may be intended to illuminate), and potentially cause accidents. Clutter is particularly noticeable on roads where the street lights are badly designed, or where brightly lit advertising surrounds the roadways.
Skyglow: refers to the “glow” effect that can be seen over populated areas.

It is the combination of all light reflected from what it has illuminated escaping up into the sky and from all of the badly directed light in that area that also escapes into the sky, being scattered (redirected) by the atmosphere back toward the ground.

Impact of light pollution:

Wastes Energy and Money:
- Lighting that emits too much light or shines when and where it’s not needed is wasteful. Wasting energy has huge economic and environmental consequences.
Disrupting the ecosystem and wildlife:
- Plants and animals depend on Earth’s daily cycle of light and dark rhythm to govern life-sustaining behaviours such as reproduction, nourishment, sleep and protection from predators.
- Scientific evidence suggests that artificial light at night has negative and deadly effects on many creatures including amphibians, birds, mammals, insects and plants.
  - Ex: A study has now shown how nocturnal dung beetles are forced to search for cues in their immediate surroundings when they can no longer navigate using natural light from the night sky.
  - The effect of light in the form of fire or lamps attracting migratory and non-migratory birds at night, especially when foggy or cloudy, has been known since the 19th century and was and still is used as a form of hunting. The reasons for disorientation of birds through artificial night lighting are not well known. Experts suggest that the navigation of birds using the horizon as orientation for the direction is disrupted by lighting and sky glow.
Harming human health:
- Like most life on Earth, humans adhere to a Circadian Rhythm — our biological clock — a sleep-wake pattern governed by the day-night cycle. Artificial light at night can disrupt that cycle.

Reduction of Light Pollution

Reducing light pollution implies many things, such as reducing sky glow, reducing glare, reducing light trespass, and reducing clutter.
The method for best reducing light pollution, therefore, depends on exactly what the problem is in any given instance. Possible solutions include:

Utilizing light sources of minimum intensity necessary to accomplish the light’s purpose.
Turning lights off using a timer or occupancy sensor or manually when not needed.
Improving lighting fixtures, so that they direct their light more accurately towards where it is needed, and with less side effects.
Adjusting the type of lights used, so that the light waves emitted are those that are less likely to cause severe light pollution problems.
Evaluating existing lighting plans, and re-designing some or all of the plans depending on whether existing light is actually needed.

Recommendations

Light only where needed
Don’t overlight
Don’t waste light
Shine light downwards, using shields and reflectors
Light only when needed – use sensors where possible
Light with energy efficient sources such as LED’s and compact fluorescents.
Much more research is needed on the effects of light pollution
Public and government awareness shall be intensified in view of the value of protection, avoidance and decrease of light pollution. Public opinion would need to be shifted regarding light trespass and “second hand” light, the wastefulness of excessive night lighting and the importance of using the right lighting for the right situation.
Legislation needs to be developed to support and require dark sky-friendly lighting through by-laws, modified engineering standards and building codes.