Light pollution now has become a big problem and led to much waste in our society. It has been estimated that 30% of the electricity generated for outdoor illumination is wasted. Important, too, are the environmental costs of producing the energy to power wasted light. For example, for every kilowatt-hour of electricity used, almost two pounds of carbon dioxide and almost two grams of sulphur dioxide are emitted into the environment. (46) Thus by simply eliminating wasted light, those amounts can be substantially reduced with no negative effect on necessary lighting and with decidedly positive environmental benefits for the region.
For individuals and families another significant issue is that of light intrusion, the spilling of un- wanted light onto private property. This concern is already addressed in some local zoning codes where maximum light levels at property lines are established. (47) But as the problem becomes more common, homeowners may also sense tha
我来回答:
