Ozone gas (O3) in the upper atmosphere shields Earth from the Sun's dangerous ultraviolet radiation. Since the early 1980s, scientists have been aware that manmade chlorofluorocarbons (CFCs) destroy atmospheric ozone worldwide. The greatest losses have occurred at the poles; the Antarctic ozone "hole" is most extreme in October.
To learn more about the ozone hole and what causes it, explore the animation
below, which shows ozone measurements across the globe obtained by NASA's
Total Ozone Mapping Spectrometer (TOMS) instrument. Ozone levels are shown
in measurements of dobson units; the "hole" represents ozone levels lower
than 220 dobson units.
Satellites provide scientists with a
picture of what's happening daily over the entire Earth. The United States
satellite measurement program for ozone, run jointly by NASA and the
National Oceanic and Atmospheric Administration (NOAA), has measured ozone
distribution by season, latitude, and longitude since 1978.
Data Sources:
- Total Ozone Mapping Spectrometer
http://toms.gsfc.nasa.gov/
- Aeronomy Laboratory
http://www.al.noaa.gov/
- TheOzoneHole
http://www.theozonehole.com/index.htm