Light pollution occurs when too much artificial illumination enters the night sky and reflects off of water droplets and dust particles in the air causing a condition known as skyglow. Unmanaged glare from improperly aimed and unshielded light fixtures crossing property lines is also considered light pollution.
- wastes energy;
- prevents us from seeing the stars at night;
- distracts and
sometimes temporarily blinds nighttime drivers; and
- causes disruptions in
sleep patterns which can lead to sleep deprivation and secondary problems such
as vehicle accidents and poor school or job performance.
In the Houston area, common light pollution complaints include being unable to sleep
because of a neighbor's outdoor lights, street lights, or lights from a nearby
freeway. Most public lighting can be redirected to lessen the unwanted effects
of lighting; judicious use of vegetation and light-blocking draperies can also
Freeway traffic, trains, buses, lawn mowers, leaf blowers, helicopters,
construction noise, low-flying recreational planes, jet skis, air-conditioning
units, and parking garage fans are among some of the sources of Houston-area
noise. Exposure to noise levels higher than 85 decibels for long periods of time can cause
permanent hearing damage, but much lower levels have been shown to cause stress,
increase blood pressure, cause sleep disturbances which affect sleep quality as
well as mood and performance (Griefahn
and Spreng 2004), and in children chronically exposed to noise, lower reading and math scores
(Stansfeld S, 2000).
Houston's city council passed a
noise ordinance for residential areas, setting the maximum decibel reading at 65 during the day and 58 during the evening. Loud garden and lawn machinery are prohibited between 8 p.m. to 7 a.m.
Certain work conditions have the potential to harm hearing. The Occupational Safety and Health Administration
requires that a workplace louder than 90 decibels for duration longer than eight hours must enforce earplug usage for employees. Construction workers
are at particular risk in the Houston area.
The Noise Pollution
Clearinghouse, a national nonprofit citizen's group, maintains an extensive
library on the effects of noise on human health and ways to reduce urban noise.