Reducing light pollution

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. 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. Mercury, metal halide and above all first generation of blue-light LED road luminaries are much more pollutant that sodium lamps: Earth atmosphere scatters and transmits blue light better than yellow or red light. It is a common experience observing "glare" and "fog" around and below LED road luminaries as soon as air humidity increases, while orange sodium lamp luminaries are less prone to show this phenomenon. Evaluating existing lighting plans, and re-designing some or all of the plans depending on whether existing light is actually needed.