Is the ozone layer comprised solely of oxygen?
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.
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
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!
(Dr. Mabel Rodrigues)
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Update: June 2012