[29] Ozone Hole / 臭氧洞, 2004

A second permanent hole in the ozone was detected at the North Pole in 1990. There are early indications that legislation banning CFC and halons use is having a positive effect.

第二個永久臭氧層破洞在1990年於北極被發現。在禁用氟氯碳化物與海龍的立法通過後,目前已從早期跡象中察覺到正面的效果。