Answer to Question #110067 in General Chemistry for Arnasia

Question

In Newman and Oman’s simulated experiment, what did they set as the cause for ozone depletion?

Answer 1

Atmospheric physicists Paul Newman and Luke Oman built a simulation of the Earth’s atmosphere and then proceeded to strip away our protective ozone layer. Their computer model reproduced the chemistry and circulation of the air; the natural variations in temperatures and winds; and the minor changes in the amount of energy received from the sun. Newman and Oman then added ozone-destroying chemicals to the atmosphere at a rate of 3% more per year—on top of what was already in our 1970s atmosphere. For several months, they ran their model on a supercomputer and reproduced about 80 years of simulated Earth time. They called their experiment "The World Avoided."

y the year 2020 in the simulation, 17% of the Earth's protective ozone layer vanished. Holes in the ozone layer formed not just over Antarctica—as they currently do each spring—but over the Arctic, too. By 2040, the ultraviolet (UV) index, the measure of the sunburn-causing radiation reaching the Earth's surface, rose as high as 15 on summer days in mid-latitude cities such as Washington, D.C. (A UV index of 10 is considered very high today and quickly leads to sunburn if you don't wear sunscreen.)

In the simulated future, two-thirds of the planet's ozone layer disappeared by 2065. Ozone holes swirled over both poles all year long, and most ozone disappeared from the tropics, too. The intensity of UV radiation reaching the Earth's surface doubled—levels that would increase DNA mutations in human and animal cells, suppress our immune systems, and increase the incidence of cataracts and skin cancer.

So it was found at high altitudes, where conditions differ from the earth's surface, chlorofluorocarbons, which accumulated over the years as a result of human industrial activity, destroy the ozone layer

Only in the 1970s did chemists learn that CFCs decompose into chlorine atoms under the influence of intense ultraviolet radiation from the sun. A chlorine atom can react with ozone to form an oxygen (O2) molecule and a chlorine monoxide (ClO) molecule, and the chlorine atom is “regenerated” when the chlorine monoxide molecule reacts with another ozone molecule. The chemical reactions are as follows:

The net result (2O3 à 3O2) is that one chlorine atom destroys two ozone molecules and is regenerated in the process, allowing it to react over and over again. So, a single chlorine atom can destroy thousands of ozone molecules. And because CFCs are removed very slowly from the atmosphere, their ozone-depleting power persists for decades after they are emitted.

Therefore, ozone-depleting chemicals cause ozone depletion