甚麼是光害? What is Light Pollution?

「光害」(又稱光污染)是一種因過度使用人為室外照明,而對自然環境和生態等引起的負面影響。人為室外照明包括街燈、霓虹招牌、廣告版照明等。設計不良的室外照明將光線直接照射或反射上天空,大氣中的雲、霧、懸浮粒子等污染物會將這些光線散射開,導致夜空被照亮,可見星星的數目因夜空的對比下降而減少。

"Light Pollution" is a form of environmental degradation in which excessive artificial outdoor lightings, such as street lamps, neon signs, and illuminated signboards, affect the natural environment and the ecosystem. The wasteful light emitted directly upwards or reflected upwards from poorly-designed artificial light sources can be scattered by clouds, fog, and pollutants like suspended particulates in the atmosphere. The night sky is thus brightened, leading to a reduced number of stars visible in the sky due to a decrease of the light contrast.