How do Chlorofluorocarbons Affect Ozone Levels?
The production and destruction of ozone in the stratosphere are nearly in balance, thus we say ozone is in a steady state. The steady state means that for every ozone molecule that is destroyed, one is produced. This steady state is imbalanced by chlorine chemistry that increases the loss rate of ozone and leads to a lower steady state level of ozone. Most of the chlorine present in the stratosphere is the result of chlorofluorocarbons (CFC’s) produced by humans. CFC’s were used heavily as a coolant in refrigerators and air conditioners, as a propellant in aerosol cans, and other uses from the 1940’s to the 1980’s. The production of CFC’s was banned in developed countries in 1995. CFC’s were considered safe because CFC’s are inert or non-reactive. While it is true that CFC’s are inert in the troposphere, they are not inert in the stratosphere. In the presence of high energy UV light in the upper stratosphere, the carbon-chlorine bond is broken. This produces a free chlorine atom (Cl) t
