OUR OZONE LAYER IS INVOLVED IN A NATURAL PROCESS CALLED THE OZONE-OXYGEN CYCLE. THE COMPLEX PROCESS CONVERTS THE UV LIGHT INTO HEAT.
THIS IS BROKEN DOWN INTO 3 BASIC SUBHEADINGS: CREATION, OZONE-OXYGEN AND REMOVAL.
THE STEPS OF THIS PROCESS ARE AS FOLLOWS:
1. Creation: an oxygen molecule is split by stronger frequency UV light into two separate oxygen molecules. –THIS FORMULA RELATES TO THIS STEP: O2 + UV → 2O
Each oxygen atom then quickly combines with an oxygen molecule to form an ozone molecule:
O + O2 → O3
2. The ozone-oxygen cycle: the ozone molecules formed by the reaction above absorb radiation having a wavelength between 240 and 310 nm. The triatomic ozone molecule becomes diatomic molecular oxygen plus a free oxygen atom:
O3 + (240 nm < radiation < 310 nm) → O2 + O
The atomic oxygen produced quickly reacts with another oxygen molecule to reform ozone:
O + O2 → O3 + K.E.
Where "K.E." denotes the excess energy of the reaction which is manifested as extra kinetic energy. These two reactions form the ozone-oxygen cycle, in which the chemical energy released when O and O2 combine is converted into kinetic energy of molecular motion. The overall effect is to convert penetrating UV-B light into heat, without any net loss of ozone. This cycle keeps the ozone layer in a stable balance while protecting the lower atmosphere from UV radiation, which is harmful to most living beings. It is also one of two major sources of heat in the stratosphere (the other being the kinetic energy released when O2 is photolyzed into O atoms).
3. Removal: if an oxygen atom and an ozone molecule meet, they recombine to form two oxygen molecules:
2 O· → O2
The overall amount of ozone in the stratosphere is determined by a balance between production by solar radiation and removal. The removal rate is slow, since the concentration of O atoms is very low.
Certain free radicals, the most important being hydroxyl (OH), nitric oxide (NO) and atoms of chlorine (Cl) and bromine (Br), catalyze the recombination reaction, leading to an ozone layer that is thinner than it would be if the catalysts were not present.
Most of the OH and NO are naturally present in the stratosphere, but human activity, especially emissions of chlorofluorocarbons (CFCs) and halons, has greatly increased the Cl and Br concentrations, leading to ozone depletion. Each Cl or Br atom can catalyze tens of thousands of decomposition reactions before it is removed from the stratosphere.
THIS IS BROKEN DOWN INTO 3 BASIC SUBHEADINGS: CREATION, OZONE-OXYGEN AND REMOVAL.
THE STEPS OF THIS PROCESS ARE AS FOLLOWS:
1. Creation: an oxygen molecule is split by stronger frequency UV light into two separate oxygen molecules. –THIS FORMULA RELATES TO THIS STEP: O2 + UV → 2O
Each oxygen atom then quickly combines with an oxygen molecule to form an ozone molecule:
O + O2 → O3
2. The ozone-oxygen cycle: the ozone molecules formed by the reaction above absorb radiation having a wavelength between 240 and 310 nm. The triatomic ozone molecule becomes diatomic molecular oxygen plus a free oxygen atom:
O3 + (240 nm < radiation < 310 nm) → O2 + O
The atomic oxygen produced quickly reacts with another oxygen molecule to reform ozone:
O + O2 → O3 + K.E.
Where "K.E." denotes the excess energy of the reaction which is manifested as extra kinetic energy. These two reactions form the ozone-oxygen cycle, in which the chemical energy released when O and O2 combine is converted into kinetic energy of molecular motion. The overall effect is to convert penetrating UV-B light into heat, without any net loss of ozone. This cycle keeps the ozone layer in a stable balance while protecting the lower atmosphere from UV radiation, which is harmful to most living beings. It is also one of two major sources of heat in the stratosphere (the other being the kinetic energy released when O2 is photolyzed into O atoms).
3. Removal: if an oxygen atom and an ozone molecule meet, they recombine to form two oxygen molecules:
2 O· → O2
The overall amount of ozone in the stratosphere is determined by a balance between production by solar radiation and removal. The removal rate is slow, since the concentration of O atoms is very low.
Certain free radicals, the most important being hydroxyl (OH), nitric oxide (NO) and atoms of chlorine (Cl) and bromine (Br), catalyze the recombination reaction, leading to an ozone layer that is thinner than it would be if the catalysts were not present.
Most of the OH and NO are naturally present in the stratosphere, but human activity, especially emissions of chlorofluorocarbons (CFCs) and halons, has greatly increased the Cl and Br concentrations, leading to ozone depletion. Each Cl or Br atom can catalyze tens of thousands of decomposition reactions before it is removed from the stratosphere.
THIS IS A DIAGRAM OF THE OZONE OXYGEN CYCLE. THIS PICTURE WAS FROM THE U.S ENVIROMENTAL PROTECTION AGENCY. TO SEE THIS WEBSITE, PRESS THE LINK BELOW:
http://www.epa.gov/ozone/science/process.html
http://www.epa.gov/ozone/science/process.html