| environ. |
atmospheric ozone A triatomic molecule of oxygen; a natural constituent of the atmosphere, with the highest concentrations in the ozone layer or stratosphere; it is found at a level between 15 and 30 km above the Earth, which prevents harmful ultraviolet B radiation, which causes skin cancer and threatens plant life, from reaching the ground. The fragile shield is being damaged by chemicals released on Earth. The main chemicals that are depleting stratospheric ozone are chlorofluorocarbons (CFCs), which are used in refrigerators, aerosols and as cleaners in many industries and halons, which are used in fire extinguishers. The damage is caused when these chemicals release highly reactive forms of chlorine and bromine (三个氧原子构成的分子；大气中的自然组成部分之一，在臭氧层或平流层含量最高；在地表上15km到30km被发现，可以阻止有害的紫外线到达地表，这种紫外线会引发皮肤癌，威胁植物生命。这层脆弱的防护盾正在被地球释放的化学物损坏，其中的主要化学物为含氯氟烃 (CFC)，这种物质在冰箱中，气溶胶中用到。也被当作清洁剂，用在工业生产及灭火器中的碳、溴或卤的气体化合物中。当这些化学物释放高度放射性的氟和氯时，臭氧层便会受到损害。) |
