Depletion Of The Ozone Layer :: essays research papers

The ozone layer diminishes more each year. As the area of polar ozone depletion (commonly called the ozone hole) gets larger, additive ultraviolet rays are allowed to pass through. These rays cause cancer, cataracts, and lowered immunity to diseases.1 What causes the depletion of the ozone layer?     In 1970, Crutzen first showed that nitrogen oxides produced by decaying nitrous oxide from soil-borne microbes react catalytically with ozone hastening its depletion. His findings started seek on "global biogeochemical cycles" as well as the effects of supersonic transport aircraft that release nitrogen oxide into the stratosphere.2      In 1974, Molina and Rowland found that human-made chlorofluorocarbons used for making foam, make clean fluids, refrigerants, and repellents transform into ozone-depleting agents.3     Chlorofluorocarbons stay in the atmosphere for several decades due to their long tropospheric lifeti mes. These compounds are carried into the stratosphere where they undergo hundreds of catalytic cycles with ozone.4 They are broken down into chlorine atoms by ultraviolet radiation.5 Chlorine acts as the catalyst for breaking down atomic atomic number 8 and molecular ozone into two molecules of molecular oxygen. The basic set of reactions that involve this exercise are                    Cl + O3 -->ClO + O2 and                    ClO + O -->Cl + O2     The net result                    O3 + O -->2O2     Chlorine is initially removed in the first equation by the reaction with ozone to form chlorine monoxide. Then it is regenerated through the reaction with monatomic oxygen in the second equation. Th e net result of the two reactions is the depletion of ozone and atomic oxygen.6Chlorofluorocarbons (CFCs), halons, and methyl banality are a few of the ozone depletion substances (ODS) that break down ozone under intense ultraviolet light. The bromine and fluorine in these chemicals act as catalysts, reforming ozone (O3) molecules and monatomic oxygen into molecular oxygen (O2).In volcanic eruptions, the sulfate aerosols released are a natural cause of ozone depletion. The hydrolysis of N2O5 on sulfate aerosols, coupled with the reaction with chlorine in HCl, ClO, ClONO2 and bromine compounds, causes the breakdown of ozone. The sulfate aerosols cause chemical reactions in addition to chlorine and bromine reactions on stratospheric clouds that destroy the ozone.8     Some ozone depletion is due to volcanic eruptions. digest of the El Chichon volcanic eruption in 1983 found ozone destruction in areas of higher aerosol concentration (Hofmann and Solomon, "Ozone Destruction through Heterogeneous Chemistry next the Eruption of El Chichon"). They deduced that the "aerosol particles act as a base for multiphase reactions leading