# Talk:Ozone

## Theory of CFCs breaking down O3

Ed, just wondering why you said it was a theory that O3 is broken down by chlorofluorocarbons? It has been observed.
Here is the common chemical reaction:
CFCl3 + UV(~310nm) ==> Cl + garbage
Cl +O3 ==> ClO + O2
(UV radiation breaks down a CFC molecule and releases a free chlorine atom. The chlorine atom reacts with ozone breaking it down to molecular oxygen plus highly unstable chlorine monoxide.)

--TimS 17:46, 8 May 2007 (EDT)

What I said was:

Some activists claimed that this ozone layer has been threatened in recent decades by the release of chlorofluorocarbons, on the theory that these act as catalysts to break down the O3 molecules.

You have to take all three emphasized words together. They claim there was a threat to the atmosphere. Their claim was entirely based on theory - not on observation.

It's like some of the evolutionary claims about biochemistry: someone theorizes that the flagellum or the eye could come into being as the result of gradual accumulation of helpful mutations. It's just a theory - not a fact - until it is proven.

Newton's theory of gravitation is also based on a formula:

$F = \frac{GMm}{r^2}$

But it can't be called a "Law" of motion unless it fits the observed facts (see astronomy). --Ed Poor 17:53, 8 May 2007 (EDT)

It is in general chemistry textbooks from which I teach that light breaks the C-Cl bond, and that the Cl* can then abstract an oxygen atom from a ozone molecule. That can be determined by simple bond energies. This is not a liberal conspiracy. Sterile 17:59, 8 May 2007 (EDT)

Hey, Sterile, I rearranged the page a little, to try to make that image you made look better (the frame was sort of awkward - I thought). Also, some of the text in it doesn't look like clean .gif text - was the iamge resized at all after you created it? Anyway, it's great having the cataytic reaction process shown clearly. Human 20:38, 8 May 2007 (EDT)