Recorded at its deepest point in ozone layer

The ozone hole above the South Pole, recorded at its deepest point on 9 October, was measured at 102 Dobson Units, the 16th highest in 26 years of readings.

Paul Newman, chief scientist for atmospheres at NASA's Goddard Space Flight Center, in Greenbelt, Maryland, says, "The colder than average temperatures in the stratosphere this year caused a larger than average ozone hole.

"Even though it was relatively large, the area of this year's ozone hole was within the range we'd expect given the levels of manmade ozone-depleting chemicals that continue to persist in the atmosphere."

The Antarctic ozone hole appears in the spring months of August and September. Satellites and instruments carried high into the atmosphere by balloons and others on the ground are used to check the size of the ozone hole, the ozone in the stratosphere and the level of problem chemicals.