Four new man-made, ozone-destroying chemicals have been discovered in the upper atmosphere, and appear to be slowing the recovery of the ozone hole, according to LiveScience.
The ozone hole over Antarctica has been gradually healing ever since an international treaty known as the Montreal Protocol began limiting the production of ozone-depleting chemicals in 1989. These chemicals, known as chlorofluorocarbons (CFCs), were commonly used in refrigerators, air conditioners and aerosols until they were found to react with and break down ozone molecules in the Earth's protective ozone layer. The treaty was created to significantly cut CFC emissions and allow the ozone hole to completely close, potentially by 2050.
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