# Do swimming pools deplete the ozone?

I believe that most people know that CFCs deplete the ozone... as does free chlorine. I have read that pool chlorine is not a factor because, it is "rapidly converted to forms that dissolve in water and therefore are removed from the lower atmosphere." and/or "ends up as hydrochloric acid or sodium chloride."

So, the premise is that bleach simply won't react with carbon in the soil to produce ozone depleting chemicals (ODCs)? Or is the mind boggling complexity of chlorine in the environment sufficient to say that it must be gone?

I know that bleach (and/or chlorine gas) reacts with VOCs (like acetone, to make chloroform). Bleach will also release chlorine gas (Cl2) in conjunction with mild acids or even just carbon dioxide. And most importantly, chloramines (which evaporate from the pool) will react with ozone or UVs to produce more bleach.

So I'm wondering, is bleach (especially from swimming pools) really not that bad?

• CFCs contain Flourine, no chance they are produced from dirt and simple bleach. And yes, all the lowly chlorinated compounds that can appear from reation of usual environmental substances with chlorine bleach are much too reactive and unstable to have a good chance of diffusing up to the ozone layer. – Karl Aug 19 '16 at 19:50
• @Karl wow, duh... I meant ODCs. Boy, I can be stupid sometimes – Ben Welborn Aug 19 '16 at 21:16
• Bleach in low concentrations will not make chloroform etc., and the lowly chlorinated compounds that do appear are environmentally problematic, but do not diffuse up to the ozone layer, because they are destroyed by reaction with UV/atmospheric dust/O2 etc. before. – Karl Aug 21 '16 at 16:32

## 1 Answer

I've heard that question before (which is why I asked). So, to head off any potential urban legends...

There is evidence that the regulations against CFC's are making a difference in the loss of ozone. There's a nice little synopsis of the situation here: The Ozone Hole

• That graph on the right looks like stockbroker chart analysis. Significance: zero. ;-) I'd like to see a good graph, convincingly showing that the ozone hole is indeed recovering (like this years newspapers said). – Karl Aug 22 '16 at 18:40