ozone shield 是什么意思

	1.	In the upper atmosphere , ozone shields the earth from the harmful ultraviolet radiation 臭氧在大气层的作用是阻挡太阳释放出来的有害紫外线。
	2.	In the upper atmosphere , ozone shields the earth from the harmful ultraviolet radiation 臭氧在大气层的作用是阻挡太阳释放出来的有害紫外线。
	3.	They must campaign to repair the ozone shield , halt the greenhouse effect , preserve soils and save the tropical rainforest 他们为了修护臭氧层,遏止温室效应,保护土壤和拯救热带雨林,必须奔走游说。
	4.	In october 1991 it was reported that the ozone shield , which protects the earth ' s surface from harmful ultraviolet10 radiation , had dwindled11 to the lowest level recorded over antarctica since 1975 when measurements were first taken 据报道， 1991年10月，南极上空防止地球表面遭受有害紫外线辐射的臭氧层，萎缩至1975年开始有测量记录以来的最低点。

ozone shield是什么意思