Light pollution affects the quality of life for all of us, because:
violates our right to privacy when not shielded light sources illuminates our property at night (Light Trespass). Many communities have laws protecting these situations.
violates our right to rest for the night in the case of lighting of our windows at night (often even the thick curtains or blinds not help).
too much artificial light at night affects our health, disturbing the balance of hormones in the bodies. Artificially induced light at night affects the ability of the pineal to produce melatonin (hormone of sleep) through the specialized cells in the retina. Low levels of melatonin can cause the development of cancer cells (people who work night shifts have a 60% greater risk of developing breast cancer). Studies have shown that even minimal amount of light penetrating through the eyes within a few hours of sleep there are significant. Moreover, this effect is cumulative over a long time interval.
light pollution severely limits our ability to see at night through blinding by the bright street lighting. The eye can easily adapt to the low light, but adapts to the brightest point in the visual field. When the light source is exposed, it is always brighter than the illuminated object (ie blinding)! As a result the sharp shadows are created (the so-called "corridors of the dark").
unwanted light spills across the sky without purpose, contributing to the so-called night greenhouse effect. It is estimated that the U.S. consume energy per year for nearly 1.5 billion USD a year on lighting the sky (not counting tresspassing area). This is a total waste of about 6-8 billion USD per year
Light pollution interferes or even impossible to perform astronomical observations, and even the perception of the stars.
