Why Antarctica 1. Strong winds blowing around the continent form what is known as the "polar vortex" - isolating the air over Antarctica from the rest of the world. 2. Polar Stratospheric clouds form. Clouds don't normally form in the stratosphere and these turn out to have the effect of concentrating the pollutants that break down the ozone.

Ozone Depletion in the Stratosphere Stratospheric ozone layer Normal levels of ozone Reduced levels of ozone Dobson Units 100DU=1mm 1DU =.01mm

Ozone Hole?  Normally 300 Dobson Units / Equivalent to a layer of ozone 3mm thick or two pennies high  One dime or 220 Dobson Units = thin  Below 220 Dobson Units = depleted area or a “hole”

The Hole Sept

Ozone Depletion in Stratosphere CFCs / HCFC’s / Bromine / Halons

Ozone Depletion

Quick Global Response Montreal Protocol stipulated a reduction in CFCs - In 1987, the Montreal Protocol was signed by many nations who agreed to reduce their emissions of CFC's to a half (of the 1987 levels) by  Full recovery of ozone levels is not likely before 2068 and regular improvement not likely until  Ozone depleting gases do appear to be trending downward but have long lifespans of 10’s to 100’s of years.

Ground level Ozone – O 3  Component of photochemical SMOG  Pollutant in the troposphere, beneficial in the stratosphere  Strong oxidizing agent  Lung irritant, eye irritant  1980 – 2009  30%  Blue skies don’t necessary equate to clean air – ozone is colorless

Acid Deposition

Measuring Acidity

Power Plant

Acid Deposition How Acid Deposition Develops

Effects of Acid Deposition