“This year we saw an ozone hole that was just below average size,” said Paul A. Newman, chief scientist for Earth Sciences at NASA's Goddard Space Flight Center in Greenbelt, Maryland. “What we’re seeing is consistent with our expectation and our understanding of ozone depletion chemistry and stratospheric weather.”
At its peak on Sept. 28, 2016, the ozone hole extended across an area nearly three times the size of the continental United States. The average area of the hole observed since 1991 has been roughly 10 million square miles.
In 2015 the ozone hole grew to 10.9 million square miles, 2 million square miles larger than this year, before returning to relatively normal summer levels. Its larger size last year was due to colder-than-average temperatures in the stratosphere that amplified the destruction of ozone by sunlight reacting with chlorine and bromine from man-made chemicals, scientists said. In 2016, warmer stratospheric temperatures constrained the growth of the ozone hole.
Ozone, which occurs naturally in small amounts in the atmosphere, is comprised of three oxygen atoms as opposed to the two that make up the much more abundant molecular oxygen.. High in the stratosphere, roughly 6 to 30 miles above the surface, the ozone layer acts like sunscreen, shielding Earth from potentially harmful ultraviolet radiation that can cause skin cancer, cataracts and suppress immune systems, as well as damage plants. Ozone is also one of the primary greenhouse gasses that regulate Earth’s temperature.
At its peak on Sept. 28, 2016, the ozone hole extended across an area
nearly three times the size of the continental United States. The purple
and blue colors are where there is the least ozone, and the yellows and
reds are where there is more ozone.https://www.nasa.gov/feature/Goddard/2016/antarctic-ozone-hole-attains-moderate-size
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