Ozone Trivia
Save our Sky, Protect Yourself, Protect the Ozone Layer.
Home | General Information | National Compliance Strategies and Plan | Policies and Legislations | Projects and Activities | Downloadable Forms | Public Awareness | Ozone Trivia | Directory | Links

What is the ozone layer?

Ozone is a gas that is naturally present in our atmosphere. Because an ozone molecule contains three oxygen atoms, It has the chemical symbol O3. The word ozone is derived from the Greek word ozein, meaning to “to smell.” Ozone has a pungent odor that allows it to be detected even in very low amounts. Ozone molecules have a relatively low abundance. For every ten million air molecules, there are only three ozone molecule.
What is the “ozone hole” and where is it located?
... there are only three ozone molecules

for every ten million air molecules...

Ozone is poisonous, and once inhaled, may be fatal. Fortunately, most ozone (about 90%) is found in the stratosphere, a region that begins about 10 to 16 kilometers above the earth’s surface and extends up to about 50 kilometers. The large amount of ozone in the stratosphere is referred to as ozone layer. Ozone found in the stratosphere (also known as stratospheric ozone) is considered “good ozone” because it protects the earth from harmful ultraviolet (UV) rays.

The remaining 10% of atmospheric ozone is in the troposphere, the region closet to earth. Ozone found in the earth’s surface is formed from pollutants and is considered “bad ozone” because it is harmful to humans and plant and animal life.

What is the ozone layer and why is it important to all life froms on earth?
The ozone layer is thin, fragile shield that envelops the earth efficiently and effectively filters and screens 90% of the sun’s harmful ultraviolet-B radiation (UV-B) and completely screens out lethal ultraviolet-C radiation (UV-C). It is located 20 to 40 kilometers above the earth’s surface.

Damage to ozone layer will naturally mean the entry of harmful UV rays into the atmosphere. Without the ozone layer, there will be no life on earth.

Ozone molecules are dispersed in the stratosphere and therefore the physical thickness of the ozone layer is tens of kilometers. However, if all ozone molecules are brought together and uniformly distributed into a gas layer over the globe, the resulting layer of pure ozone would have a thickness of three to five millimeters.

"Ozone hole” is not a literal hole in the atmosphere. It refers to the thinning of the ozone layer or the loss of the blocking effect of ozone against ultraviolet rays, allowing the entry of greater concentrations of UV-B putting all life forms at risk. The ozone hole was first observed over the Antarctic area in the early 1980’s.Antarctic ozone depletion is seasonal, occurring primarily in late winter and spring (August-November). Today, the size of the ozone hole is about 11.1 million square miles, slightly larger than the North American continent.
go to top
next 1 2 3 4 5