The ozone is a thin layer of atmosphere that protects us from the sun. It wraps all the way around the Earth, about 10 to 30 miles straight up. From the beginning of time, the ozone has blocked the sun’s most dangerous ultraviolet rays from reaching us. It continues to
do so even today.
Each ozone molecule is made up of three small oxygen atoms that act like a safety net to catch most of the UV rays and keep them from getting down to the Earth’s surface. There’s been a problem in the last few decades though.
The ozone layer is being depleted with the higher usage of products that emit chlorofluorocarbons, or CFC’s. Right now, only a small region of Antarctica is actually covered by ozone because such a large hole is forming over the area. The ozone layer is thinning even over more heavily populated areas like North America and Australia.
What Depletes the Ozone Layer?
The depletion of ozone is caused by the release of chlorofluorocarbons (CFCs) and other ozone depleting substances (ODS). Some common ODS are refrigerants, insulating foams, and solvents. The following focuses mostly on CFCs, but is relevant to all ODS. Although CFCs are heavier than air, they are eventually carried into the stratosphere in a process that can take as long as 2 to 5 years.
Measurements of CFCs in the stratosphere are made with the help of balloons, aircraft, and satellites. When CFCs reach the stratosphere, the ultraviolet radiation from the sun causes them to break apart and release chlorine atoms which react with ozone, starting chemical cycles of ozone destruction that deplete the ozone layer. One chlorine atom can break apart more than 100,000 ozone molecules.
Other chemicals that damage the ozone layer include methyl bromide (a pesticide), halons (used in fire extinguishers), and methyl chloroform (a solvent used in industrial processes). As methyl bromide and halons are broken apart, they release bromine atoms, which are 40 times more destructive to ozone molecules than chlorine atoms. CFCs and other ODS are heavier than air. In a still room, they would pool on the floor, but the atmosphere certainly not still. Numerous measurements have proven that these molecule are mixed nearly uniformly throughout all the trophosphere over the entire earth. In the same way that vinegar and oil normally separate when still, but mix when shaken, ozone depleting substances and air are thoroughly stirred together by winds in the troposphere.