Light pollution


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This is very simple ppt on light pollution with a little bit of description.

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Light pollution

  1. 1. Jagriti Gupta
  2. 2. México City at Night 2005 Light pollution, also known as photo pollution or luminous pollution, is excessive or obtrusive artificial light.
  3. 3. Light pollution  Light pollution is a broad term that refers to multiple problems, all of which are caused by inefficient, unappealing, or (arguably) unnecessary use of artificial light. Specific categories of light pollution include light trespass, over-illumination, glare, light clutter, and sky glow. A single offending light source often falls into more than one of these categories. An example of a light pollution source, using a broad spectrum metal halide lamp, pointing upward in Uniqema Gouda, the Netherlands.
  4. 4. This time exposure photo of New York City at night shows sky glow, one form of light pollution. Light pollution
  5. 5. Light pollution A comparison of the view of the night sky from a small rural town (top) and a metropolitan area (bottom). Light pollution vastly reduces the visibility of stars.
  6. 6. A satellite image of Earth at night. Light pollution
  7. 7. Effects on animal and human health 1. increased headache incidence 2. worker fatigue 3. medically defined stress 4. increase in anxiety 5. animal models have been studied demonstrating unavoidable light to produce adverse effect on mood and anxiety
  8. 8.  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. Reducing light pollution
  9. 9. Reducing light pollution  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. A flat-lens cobra luminaire, which is a full- cutoff fixture,may be 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.