Describe Ozone as a Molecule Able to Act as Both an Upper Atmospheric Sheild and a Lower Atmospheric Pollutant Essay
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Ozone as a pollutant
Ozone reacts readily with other gases so is present in the troposphere for a limited time. Ozone is formed in photochemical smog (such as Nitrogen dioxide) through interaction with sunlight or diffuses into the troposphere from the stratosphere aswell as being formed from lighting and other electrical sources. Photochemical smog is found in high concentration in and around cities such as Los Angeles—known to have high levels of ozone concentrations. A study carried out in the United States in 2008 revealed that people living in Los Angeles had a 30% greater risk of dying of lung disease. Ozone is poisonous to humans and many other organisms and has been proven to cause respiratory problems, headaches, fatigue—as well as being an irritant to the nose, lungs, eyes and throat and can cause death in high concentrations. Ozone is found in low concentrations in the troposphere being on average 0.02 parts per million.
Ozone as a radiation shield
90% of ozone is present in the stratosphere where it exists as 2-8 parts per million. During the formation of ozone and the decomposition of ozone—the reactions absorb UV radiation from the sun, effectively shielding life on earth to its damaging effects. Ozone in the stratosphere is formed largely due to the interaction between light and oxygen molecules:
O₂(g) 2O(g) (absorbs high energy UV radiation).
O(g) + O₂(g) O₃(g).
The decomposition of Ozone also absorbs UV radiation:
O₃(g) O₂(g) + O(g) (absorbs moderate energy UV radiation).
O₃(g) + O(g)