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Name: Betty
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Question:
Is the ozone layer comprised solely of oxygen?



Replies:
No, it's regular air (80% nitrogen, 18% oxygen, 1% argon, 1% others). The ozone present is created by the action of sunlight on the oxygen. The wavelengths of sunlight that induce this chemistry are absorbed in the stratosphere, so they don't reach the surface. That's why the "ozone layer" is so high up.

For ozone to be formed in the lower atmosphere, some air pollution needs to be present. So human activities both create ozone in the lower atmosphere, where we don't want it, and destroy ozone in the upper atmosphere, where we do want it.

Dr. Barrans


Hi Betty!

The ozone layer or ozonosphere is the region in the upper atmosphere between 6 and 30 miles (10-50 kms) altitude, where there are appreciable concentrations of ozone. So it belongs mainly to stratosphere . The average composition of the low atmosphere(up to 15 kms includes: nitrogen, oxigen, argon,carbon dioxide, ozone, methane, nitric oxide, hydrogen, nitrous oxide, carbon monoxide, water vapour

This gases are also in the ozone layer, but the increased presence of ozone determines itself a series of chemical processes. So it is found : oxigen and hydrogen atomic, hydroxyl and methyl radicals, hydrogen peroxyde, water vapour. Also one must know that even though the ozone layer is about 40 kms (25 miles) thick, the atmosphere is very tenous, and the total amount of ozone, compared to more abundant atmospheric gases is quite small. It is mentioned (Britannica) that if all of the atmospheric ozone in a vertical column through the entire atmosphere were compressed to sea-level pressure, it would form a layer only a few tenths of a centimeter thick. And since it is so necessary...one must take a good care of it! And thanks to ask NEWTON!

Mabel
(Dr. Mabel Rodrigues)



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