Astronomy Picture of the Day . ... The ozone hole that has been a cause of concern in recent years has again reformed over Earth's South Pole . The seasonal recurrence of the ozone hole was expected, although the size of the hole has never been so large this early in the season. ... Ozone is vulnerable, though, to CFCs and halons being released into the atmosphere. ... Publications with keywords: Earth - atmosphere - ozone hole . Publications with words: Earth - atmosphere - ozone hole . ...