The hole in Earth’s ozone layer that forms over Antarctica each September was the smallest observed since 1988, NASA satellite measurements from this year have revealed. The ozone hole reached its peak extent on September 11, covering an area about two and a half times the size of the U.S. — 7.6 million square miles in extent — and then declined through the remainder of September and into October, according to scientists from NASA. Ground- and balloon-based measurements from the National Oceanic