OZONE DEPLETION

Largest Observed Ozone hole 9/06 From September 21-30, 2006 the average area of the ozone hole was the largest ever observed, at 10.6 million square miles (27.5 million square kilometres). This image, from September 24, the Antarctic ozone hole was equal to the record single-day largest area of 11.4 million square miles (29.5 million square kilometres), reached on Sept. 9, 2000. Satellite instruments monitor the ozone layer, and we use their data to create the images that depict the amount of ozone. The blue and purple colors are where there is the least ozone, and the greens, yellows, and reds are where there is more ozone.

The OZONE CYcle

Global Monthly Ave. Total Ozone Amt. This image shows the global (from 65 degrees north latitude to 65 degrees south latitude) monthly average total ozone amount for the time period 1979 through the end of 2001. The green line shows the results from Nimbus-7 TOMS instrument. The red line shows the results from the Meteor-3 TOMS instrument. The blue line shows the results from the Earth Probe TOMS instrument, which developed a fault in 2002.

This image shows the lowest value of ozone measured by TOMS each year in the ozone hole. Global average ozone is about 300 Dobson units. Before 1980 ozone less than 200 Dobson units was rarely seen. In recent years ozone near 100 Dobson units has become normal in the ozone hole. Ozone in the year 2002 ozone hole was higher than we have come to expect because of unusually high temperatures in the Antarctic stratosphere

Global Ozone if no cfc ban NASA projection from 1974 to 2060 of the impact of CFCs on the Ozone layer if they hadn't been banned.

Ozone depleting gas trends and equivalent Chlorine effect. Combined chlorine and bromine in the lower atmosphere or troposphere from the most abundant chlorinated and brominated chemicals controlled by the Montreal Protocol. These changes are reflected in the upper atmosphere stratosphere (10-25 km), where most ozone loss occurs, with a delay (due to air transport) of 3-5 years. Bromine is included as an ozone-depleting chemical because although it is not as abundant as chlorine, it is 45 to 60 times more effective per atom in destroying stratospheric ozone. Earlier measurements showed that the peak of equivalent chlorine (chlorine + 45 (or 60) times bromine) occurred at the surface between mid-1992 and mid-1994.[CMDL20010206] The observed decrease is driven by a large and rapid decline in methyl chloroform and methyl bromide, gases that are regulated internationally by the Montreal Protocol. The initial decline in methyl bromide was larger than that expected from projections given in the WMO/UNEP 2002 Scientific Assessment to Ozone Depletion

Sources of stratospheric chlorine Sources of stratospheric chlorine. According to World Meteorological Organization, Scientific Assessment of Ozone Depletion: 1998, WMO Global Ozone Research and Monitoring Project -

Effects of Ozone Thinning HUMANS; damages DNA Makes for a more intense sunburn Premature aging of skin Increased incidents of cataracts Weakened immune system More skin cancer

Effects of Ozone Thinnning MARINE LIFE Kills unicellular organisms (phytoplankton) Disrupt ocean food webs Reduce fish harvests Increases the amount of CO2 in atmosphere

Effects of Ozone Thinning Amphibians Kills their eggs (no hard shell) Future population numbers at risk Indicator species

Effects of Ozone Thinning LAND PLANTS Interfere with photosynthesis Reduced crop yield Decreased forest productivity

Effects of Ozone Thinning AIR POLLUTION Increased acid deposition Increased photochemical smog Degradation of outdoor paints/plastics/rubber Act as GHG’s