英语听力文摘 臭氧空洞

臭氧层是指大气层的平流层中臭氧浓度相对较高的部分，其主要作用是吸收短波紫外线。大气层的臭氧主要以紫外线打击双原子的氧气，把它分为两个原子，然后每个原子和没有分裂的氧合并成臭氧。臭氧分子不稳定，紫外线照射之后又分为氧气分子和氧原子，形成一个继续的过程臭氧氧气循环，如此产生臭氧层。自然界中的臭氧层大多分布在离地20—50千米的高空。臭氧层中的臭氧主要是紫外线制造。

Cleaning Up The Ozone Layer

清理臭氧层

The scientists are devoting all their time to this problem(solving ozone layer depletion) are going to be thrilled.

The problem with the ozone layer is that when certain chemicals, like chlorofluorocarbons, reach the stratosphere, they break down into chlorine and bromine,which react with the ozone and destroy it.

The plan is to somehow clean the stratosphere and get rid of these chemicals. For example, some scientists have suggested using giant lasers on top of mountains to basically break apart harmful chemicals before they reach the stratosphere.

However, research proves that this would be incredibly expensive, not to mention that the side effects aren’t clear. Scrubbing out the chemicals this way might end up causing serious environmental problems.

It would be much easier to stop releasing harmful chemicals into the atmosphere in the first place. One chlorinemolecule can break apart more than one hundred thousand ozonemolecules. Why not keep it from getting there at all? If we stopped releasing harmful chemicals today, the ozone layer would probably be back at full strength by 2050.

一些科学家花毕生的精力来解决臭氧层损耗的问题，他们将会感到很兴奋。

科学家们认为人类造成臭氧层破坏的主要原因是一些化学物质，像氯氟碳，当它们到达平流层后会分解成氯和溴，然后和臭氧发生化学反应从而破坏臭氧层。

他们计划将这些化学物质从平流层中清除。例如，有的科学家就建议在有害化学物质到达平流层之前，使用山顶上的巨型激光束从根本上将它们分离。

可是，调查研究研究表明这种方法的成本很高，更何况产生的副作用还不清楚。用这种方法清除化学物质可能会导致严重的环境问题。

首先，停止向大气中排放有害化学物质是比较简单易行的办法。一个氯分子可以分解十万多个臭氧分子。为什么不阻止氯到达臭氧层呢?如果我们现在停止排放有害化学物质，也许到了2050年，臭氧层空洞就会消失了。