to hear the weather man say
that Ozone levels were very high....
but I thought Ozone was being lost in some hole......
|A bit of clarity regarding Ozone.
Ozone (O3) is naturally created every time lightening strikes. Ozone is what you smell after a rain storm, its that wonderfully clean smell. It is also used to remove odors, like smoking or pet odors in your home. So what's the deal, is it in short supply?
Ozone, as you have learned, captures UV rays in the upper atmosphere (the stratosphere) and protects us from becoming burnt by the Sun's [UV] rays. As we add certain chemicals to the atmosphere, like CFC's from Freon and Aerosol cans, they react with Ozone to produce other molecules. For example, one CFC molecule reacts with 10000+ Ozone molecules. Think of the CFC as the PacMan and the Ozone as the dots. So as we use up Ozone there is less available to capture (absorb) the Sun's rays, thus called Ozone depletion or the Ozone hole (a tear in the chemical fabric of the stratosphere).
Ozone depletion does not contribute directly to Global Warming.
It does however, contribute indirectly by allowing more UV too
penetrate the stratosphere and reach Earth. Once the rays reach
Earth, they warm the surface and are (in-part) reflected back to the
atmosphere. Greenhouse gases like Carbon Dioxide (CO2) and
Methane (CH4) capture the rays and reflect them back to the Earth -
keeping the rays heating properties within the Earths atmosphere.
This is similar too sitting in your car on a brisk sunny fall day, but
your car's interior is warm because of the Sunlight coming through the
windshield (the greenhouse effect). The Greenhouse gases are
those contributing to Global Warming.
|But Ozone also comes from burning fossil fuels, particularly in
cars. This Ozone is not located high in the stratosphere, but
rather low in the troposphere (or tropopause). It too captures
Sunlight and becomes reactive [photo-reactive] with other chemicals like
dust and other hydrocarbons produced by combustion. Often, and
particularly on clear cool mornings in the fall, you will see this Ozone
in the atmosphere. It is one of a number of chemicals we refer to
Why then doesn't the ground level Ozone (O3) float up to the stratosphere and replace that other Ozone that we are destroying with CFC's and the like? To put it simply, Ozone is a collection of 3 Oxygen atoms, whereas the Oxygen we breath (O2) is a collection of 2 oxygen atoms. Ozone is thus heavier than Oxygen and sinks rather than floats until stirred up by wind currents and updrafts (a relatively long process). This is highly over simplified, but you should appreciate the difference between Ozone at different levels in our atmosphere.
So there are really three ways to look at Ozone: a protective agent in the stratospheric, a man-made pollutant in the tropopause / troposphere, and a clean smelling lightening induced naturally occuring chemical.