Why do holes in the ozone layer appear mainly in the polar regions?

Answer 1

The hole in the ozone layer over planet earth is caused by the interaction of man-made gasses -- CFCs or chloroflurocarbonswith sunlight which destroys ozone.

Late winter/ early spring -- August in Antarctica -- is the coldest period over the continent, because of the lack of sunrises since fall. The sunlight situation in spring over the continent is called the circumpolar vortex and the result is the lack of ozone in the lower atmospheres, because the stratospheric air cannot penetrate the cold. (Stratospheric air contains more ozone.)

Once sunrises occur and sunsets don't occur, the lower atmospheres begin to recover making September and October the prime periods during which there is a 'hole in the ozone layer' above the continent.

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Answer 2

This is because the primary cause of upper level ozone in our atmosphere is due to the interaction of sunlight and oxygen. There are only two holes or thinning areas of ozone in our atmosphere. The largest is over Antarctica during the end of it's long dark winter. The other is over the Arctic during it's winter's end also. This is due to ozone's tendency to quickly decay into oxygen. Without new ozone being formed due to the interaction of sunlight and oxygen, we see the levels of ozone quickly diminish. When the sun returns, these holes quickly disappear.

That is not to say that ALL ozone depletion is due to a lack of sun. There is also solar flares to be considered as a real issue. In fact, the largest known thinning of our ozone occurred in 1859 due to high levels of solar activity.

Answer 3

Ozone "holes" are areas of the stratosphere where ozone concentration is noticeably lower than in the rest of the stratosphere. They are not a total absence of ozone. They occur primarily over the South Pole because the mechanism for depleting the ozone (increasing the rate at which it reverts to O2) requires the surface of ice crystals to catalyze. The extreme cold over the pole helps tip the equilibrium in favor of the formation of ice crystals vs water vapor despite the very low concentration of water at stratospheric altitudes. The effect is less pronounced over the North Pole. The formation of ozone "holes" over the poles is a natural phenomena that would occur with or without human activities since volcanic eruptions and other natural phenomena release significant quantities of halogenated gases in to the atmosphere on a continual basis.

With that said, human activities have increased the amount of halogenated species released into the atmosphere and are believed to have increased the SIZE of the ozone holes, i.e. widened the distance over which the concentration is lowered.

Answer 4

It is because ozone depletion occurs in winters. It takes place in low temperatures.

Answer 5

The ozone level drops in winters. It is because depletion takes at cold weathers mainly.