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I November 2023, NASA: 2023 Ozone Hole Ranks 16th Largest, NASA and NOAA Researchers Find. The 2023 Antarctic ozone hole reached its maximum size on Sept. 21, according to annual satellite and balloon-based measurements made by NASA and NOAA. At 10 million square miles, or 26 million square kilometers, the hole ranked as the 12th largest single-day ozone hole since 1979. During the peak of the ozone depletion season from Sept. 7 to Oct. 13, the hole this year averaged 8.9 million square miles (23.1 million square kilometers), approximately the size of North America, making it the 16th largest over this period.  “It’s a very modest ozone hole,” said Paul Newman, leader of NASA’s ozone research team and chief scientist for Earth sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Declining levels of human-produced chlorine compounds, along with help from active Antarctic stratospheric weather slightly improved ozone levels this year.” The ozone layer acts like Earth’s natural sunscreen, as this portion of the stratosphere shields our planet from the Sun’s harmful ultraviolet radiation. A thinning ozone layer means less protection from UV rays, which can cause sunburns, cataracts, and skin cancer in humans. Every September, the ozone layer thins to form an “ozone hole” above the Antarctic continent. The hole isn’t a complete void of ozone; scientists use the term “ozone hole” as a metaphor for the area in which ozone concentrations above Antarctica drop well below the historical threshold of 220 Dobson Units. Scientists first reported evidence of ozone depletion in 1985 and have tracked Antarctic ozone levels every year since 1979. Antarctic ozone depletion occurs when human-made chemicals containing chlorine and bromine first rise into the stratosphere. These chemicals are broken down and release their chlorine and bromine to initiate chemical reactions that destroy ozone molecules. The ozone-depleting chemicals, including chlorofluorocarbons (CFCs), were once widely used in aerosol sprays, foams, air conditioners, fire suppressants, and refrigerators. CFCs, the main ozone-depleting gases, have atmospheric lifetimes of 50 to over 100 years. Read more here