Hi, I'm Sean Tvelia. We're here at Suffolk County Community College to discuss the importance of the stratosphere. Now the stratosphere is part of our atmosphere and we are used to the atmosphere at ground level. The atmosphere changes quite a bit as we move higher and higher in elevation and we find that the atmosphere is actually stratified. The area from the ground up to about 12 kilometers is the troposphere and the troposphere contains most of our weather and there air is constantly circulating and air is rising and falling and making most of our weather but in the stratosphere the level directly above the troposphere air behaves a little differently and there is very little vertical mixing, in other words mixing between layers in the stratosphere. Now in terms of importance this is really great for flyers, people in planes because planes when they fly through the stratosphere since there is very little vertical mixing there is very little turbulence. Now although that's important to travelers, it's really not that important. The real importance of the stratosphere is one thin layer that we know as the ozone layer. The ozone layer contains a molecule known as ozone, O3 and the ozone layer blocks harmful UV radiation and as a result, most of the UV radiation that emanates from the sun is blocked from reaching the surface of the Earth and UV radiation actually causes lots of illnesses and particularly cancer. So the importance of the stratosphere is the fact that it basically protects us from the harmful UV radiation of the sun.