The ozone hole is NOT a hole!

What exactly is the ozone hole? The ozone hole is not actually a hole. It is where the ozone layer is depleted with ozone, O3.  

There are different layers of the atmosphere around the Earth. Troposphere is 0 to about 8 to 18 km in altitude above the surface of the earth. Stratosphere is from troposphere to 50 km in altitude. Stratosphere is the region of high ozone concentration.

Picture from: http://en.wikipedia.org/wiki/File:Atmosphere_layers-en.svg

Where are ozone holes? Ozone holes are at the stratosphere over the Antarctic and the Arctic. The hole is found much bigger over the Antarctic, the region around the South Pole.  Ozone concentrations over these regions are decreasing annually.

picture from : http://en.wikipedia.org/wiki/File:160658main2_OZONE_large_350.png

This is a figure of the Earth. The blue part is the ozone hole with low ozone concentation.

How do ozone holes form over the Antarctic and Arctic? Due to very low temperature in these regions, polar vortex forms. This isolates the atmosphere from the rest of the stratosphere and causes no air movement. Polar Stratospheric Clouds or PCS form that amplify ozone depletion by the catalytic cycle of atomic halogen. They do not happen over other area in the stratosphere because the weather is not as cold as the poles.

Why do we care about the zone hole or the ozone layer? Sun emits harmful UV radiation such as UV-B and UV-C which threatens all lives on Earth. The ozone layer absorbs all UV-C and most UV-B and blocking them from reaching the Earth. The ozone hole is getting bigger every year and this means that more UV radiation can reach to all lives on Earth. Two percent increase in UV correlates with 3.5% increase in basal cell cancer (Wheeler 2012).  UV-B causes 90% of human skin cancer (Wheeler 2012).

We should use sunscreen every morning! Sunscreen decreases the amount of UV-B that can reach to our skin and blocks out UV-A.

Sources:

Wheeler, M. 2012. UBC  chemistry 302 notes.

Wikipedia. Ozone Depletion. http://en.wikipedia.org/wiki/Ozone_hole (accessed 2/ 24/ 2012)

Wikipedia. Ultraviolet. http://en.wikipedia.org/wiki/Uv (accessed 2/ 24/ 2012)

Wikipedia. Polar Stratospheric Clouds.  http://en.wikipedia.org/wiki/Polar_stratospheric_clouds(accessed 2/ 24/ 2012)

 Youtube. Sunscreens: SPF50 protects five times better than SPF10. https://www.youtube.com/watch?v=8cc8qRr7oMQ&feature=related (accessed 2/ 24/ 2012)