LIGHT POLLUTIONThe Dark Side, Our Vanishing

Night..

What is Light Pollution?• Light pollution, also known as

photopollution or luminous pollution, is excessive or obtrusive artificial light.

• Light pollution first made news in 1964, when an observatory was specially placed just to avoid light pollution

• Light pollution can be divided into two main types: (1) annoying light that intrudes on an otherwise natural or low-light setting and (2) excessive light (generally indoors) that leads to discomfort and adverse health effects.

• It is most severe in highly industrialized, densely populated areas of North America, Europe, and Japan and in major cities in the Middle East and North Africa.

Types of Light Pollution Light Trespass : occurs when

unwanted light enters one's property, for instance, by shining over a neighbor's fence.

Causes problems such as sleep deprivation or the blocking of an evening view.

Over-illumination : is the excessive use of light.

Over-illumination is responsible for approximately two million barrels of oil per day in energy wasted.

Glare : is difficulty seeing in the presence of bright light such as direct or reflected sunlight or artificial light such as car headlamps at night.

Glare from bad lighting is a public-health hazard—especially the older you become.

Light Clutter : refers to excessive groupings of lights. Groupings of lights may generate confusion, distract from obstacles and potentially cause accidents

Sky glow : 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.

Consequences Effect on Human Health &

Psychology:1. Increased headache incidence,

worker fatigue, medically defined stress,

2. Effect on mood and anxiety 3. Elevate blood pressure by about

eight points 4. Risk of breast cancer

Disruption of Eco Systems :1. Poses a serious threat in particular

to nocturnal wildlife 2. Having negative impacts on plant

and animal physiology 3. It can confuse animal navigation 4. Change predator-prey relations 5. Light pollution around lakes

prevents zooplankton, from eating surface algae

6. Lights on tall structures can disorient migrating birds

7. Sea turtles do not come to shore and nest as often

8. Migrating fish species (salmon, herring, etc.) cluster under artificial lights causing unnatural concentration of fish

Effects on Astronomy : 1. Is very sensitive to light pollution 2. Reduces the contrast between stars

and galaxies 3. In densely populated areas sky

brightness as much as 100 times brighter than is natural.

Energy Waste : 1. Lighting is responsible for one-

fourth of all electricity consumption worldwide

2. Public lighting is the single largest source of Greenhouse Gas Emissions

REDUCTION☺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 by use of full

cutoff fixtures help to reduce sky glow by preventing light from escaping above the horizontal .

☺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.

A flat-lens cobra luminaries, which is a full-cutoff fixture, is very effective in reducing light pollution. It ensures that light is only directed below the horizontal, which means less light is wasted through directing it outwards and upwards.

This kind of LED droplight could reduce unnecessary light pollution in building interiors

THANK YOU

Presentation By:

Chaitra NVI Sem