英语课程计划-the Preservation of the Ozone Layer（在线收听）

There is a special day to recognize the importance of the ozone layer. In 1995, the United Nations General Assembly decided September 16th is the International Day for the Preservation of the Ozone Layer. This is the date on which countries signed the Montreal Protocol on substances that deplete the Ozone Layer in 1987. The U.N. said it was urgent we consider the “need to preserve the ozone layer, which filters sunlight and prevents the adverse effects of ultraviolet radiation reaching the Earth's surface, thereby preserving life on the planet”. It Invited every country to devote this special day to promotion, at the national level, of concrete activities in accordance with the objectives and goals of the Montreal Protocol”.

The ozone layer is a layer in Earth's atmosphere that contains high concentrations of ozone (O3). This layer absorbs up to 99 per cent of the sun's damaging ultra-violet (UV) rays. These rays contain radiation from the sun and can give us skin cancer. They also damage plant and marine life as well as warm the temperature of the Earth. The ozone layer surrounds the Earth roughly 25km above us. Many human activities are thinning the layer. In several places, there are large holes that let in pure UV light. The chemicals used in fridges, air conditioners, foam packaging and fire extinguishers rise into the atmosphere and attack the ozone. Ozone cover is dropping by roughly four per cent a decade.