Preliminary analysis using NOAA satellite data indicates that at 18.9 million square kilometers (about 7.3 million square miles), the ozone hole over the South Pole reached its maximum annual size on September 26, 2013. Shown here is the total ozone concentration over the South Pole on September 26, 2013 using data from NOAA's Total Ozone Analysis using SBUV/2 and TOVS measurements. The "hole" is designated as the area where the total ozone concentration is below 220 Dobson units (a measure of thickness). In this animation, those values are colored red.
