updated 11/5/2008 3:35:54 PM ET 2008-11-05T20:35:54

This year's ozone hole over Antarctica was the fifth biggest on record, reaching a maximum area of 10.5 million square miles in September, NASA says.

That's considered "moderately large," NASA atmospheric scientist Paul Newman said in a statement.

NASA has tracked the size of the hole for 30 years. Last year, it was 9.7 million square miles, about the size of North America.

The hole is an area of depletion in the stratospheric ozone layer, which blocks harmful ultraviolet rays from space. Created by human-produced gases, the ozone hole generally forms in August and grows to its maximum size in September or October before breaking up.

Copyright 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Discuss:

Discussion comments

,

Most active discussions

  1. votes comments
  2. votes comments
  3. votes comments
  4. votes comments