LIGHT POLLUTIONThe Dark Side, Our VanishingNight..
What is Light Pollution?• Light pollution, also known asphotopollution or luminouspollution, is excessive or obtrusiveartificial light.• Light pollution first made news in1964, when an observatory wasspecially placed just to avoid lightpollution
• Light pollution can be divided into twomain types: (1) annoying light thatintrudes on an otherwise natural or low-light setting and (2) excessive light(generally indoors) that leads todiscomfort and adverse health effects.• It is most severe in highly industrialized,densely populated areas of NorthAmerica, Europe, and Japan and in majorcities in the Middle East and NorthAfrica.
Types of Light Pollution Light Trespass : occurs whenunwanted light enters ones property,for instance, by shining over aneighbors fence.Causes problems such as sleepdeprivation or the blocking of anevening view.
Over-illumination : is the excessive use oflight.Over-illumination is responsible forapproximately two million barrels of oilper day in energy wasted.
Glare : is difficulty seeing in the presence ofbright light such as direct or reflected sunlightor artificial light such as car headlamps at night.Glare frombad lighting isa public-healthhazard—especially theolder youbecome.
Light Clutter : refers to excessivegroupings of lights. Groupings of lightsmay generate confusion, distract fromobstacles and potentially cause accidents
Sky glow : refers to the "glow" effect that can beseen over populated areas.It is the combination of all light reflected fromwhat it has illuminated escaping up into the skyand from all of the badly directed light in thatarea that also escapes into the sky, beingscattered (redirected) by the atmosphere backtoward the ground.
Consequences Effect on Human Health &Psychology:1. Increased headache incidence, workerfatigue, medically defined stress,2. Effect on mood and anxiety3. Elevate blood pressure by about eightpoints4. Risk of breast cancer
Disruption of Eco Systems :1. Poses a serious threat in particular tonocturnal wildlife2. Having negative impacts on plant andanimal physiology3. It can confuse animal navigation4. Change predator-prey relations5. Light pollution around lakes preventszooplankton, from eating surface algae6. Lights on tall structures can disorientmigrating birds7. Sea turtles do not come to shore andnest as often8. Migrating fish species (salmon, herring,etc.) cluster under artificial lightscausing unnatural concentration of fish
Effects on Astronomy :1. Is very sensitive to light pollution2. Reduces the contrast between stars andgalaxies3. In densely populated areas skybrightness as much as 100 timesbrighter than is natural. Energy Waste :1. Lighting is responsible for one-fourthof all electricity consumptionworldwide2. Public lighting is the single largestsource of Greenhouse Gas Emissions
REDUCTION☺Utilizing light sources of minimumintensity necessary to accomplish thelights purpose.☺Turning lights off using a timer oroccupancy sensor or manually when notneeded.☺Improving lighting fixtures by use of fullcutoff fixtures help to reduce sky glow bypreventing light from escaping above thehorizontal .☺Adjusting the type of lights used, so thatthe light waves emitted are those that areless likely to cause severe light pollutionproblems.
A flat-lens cobra luminaries,which is a full-cutoff fixture,is very effective in reducinglight pollution. It ensures thatlight is only directed below thehorizontal, which means lesslight is wasted throughdirecting it outwards andThis kind of LEDdroplight could reduceunnecessary lightpollution in buildinginteriors