light pollution essay "cause,effects,reductions"

                             what is light pollution?

Light pollution occurs when artificial light intrudes on the nighttime setting. This phenomenon is pronounced around urban centers, where city lights diminish the view of stars and planets. A satellite view at night shows light pollution as glowing regions around urban areas. In addition to brightened skies around cities, light pollution also refers to any outdoor light that creates glare and interferes with the natural night environment. The National Park Service refers to a single source of light that intrudes on the night as "light trespass." 

Cause

Light pollution results from outdoor lights aimed upward or sideways --- the light scatters in the atmosphere and reflects back to the ground. The result is sky glow. Particles in the atmosphere responsible for air pollution accentuate light pollution by increasing the amount of light scatter. According to the International Dark-Sky Association, light sources that emit blue light are particularly disruptive to night skies due to greater light scattering. 

Effects

According to the National Park Service, city lights as far as 200 miles away diminish views of night skies. Light pollution is a major concern for observatories as lights from urban areas compete with lights from stars and planets, reducing visibility of the objects that observatories study. This type of pollution also affects wildlife and plants. Night lights disorient hatching sea turtles, migrating birds and nocturnal animals. Lights attract insects, which may in turn interfere with pollination of nocturnal flowers. In humans, light pollution can interfere with natural circadian rhythms by preventing the production of melatonin, the chemical that regulates sleep patterns. Low melatonin levels have been linked to increased cancer risks.

Reduction

There are ways to reduce light pollution, starting in your own neighborhood. Make sure outdoor lights reflect downward in what are called fully-shielded fixtures. Also consider exchanging high-wattage bulbs for dimmer ones and selecting warm-white lights with low emission of blue light. A great way to save energy and reduce trespassing light is to turn off outdoor lights unless needed.